Pigeon Forge, in the foothills of Tennessee’s Great Smoky Mountains, is the kind of place where it’s easy to find 50 kinds of relish to go with your burger but impossible to get a drink. Even the manager of Denny’s Diner – one of a 15-mile strip of endless fast food outlets that has sprung up on the corridor from Knoxville – raises his eyebrows when asked whether he serves alcohol. “No sir. And I made darn sure we don’t.” When he realises that I am not a teetotaller in need of reassurance, but a parched European, he changes tack: “I believe there is a hotel a few blocks down that sells liquor,” he says with the conspiratorial lack of eye contact that might accompany a drug deal.

Tennessee is the conservative America that liberal outsiders have such a hard time understanding. The advertising hoardings pulse between “Biggest Breakfast in Town” and “In God We Trust”. Inside the hotel room the Gideons Bible is not discreetly tucked away but has been left open by the maid at some verses from Psalms.

Only 30 years ago, this urban sprawl was deep in the backwoods, and just a short trek away is Locust Ridge, where Dolly Parton was born in 1946, a child of impoverished sharecroppers, sharing a log cabin with 11 siblings but without electricity or running water. Today, though, the area is home to Dollywood, Parton’s hugely lucrative entertainment empire, a place that combines stars-and-stripes patriotism, southern gluttony, Dixie nostalgia and some pretty unlikely horse-tricks.

Parton is one of the biggest stars country music has ever produced – part of the Nashville superstar triumvirate, along with Garth Brooks and Kenny Rogers, she is estimated to have sold between 50m and 100m records. In Britain, she’s best known for karaoke hits such as “Jolene” and “Islands in the Stream”. In America, however, her surgically enhanced cheekbones wouldn’t look out of place carved into Mount Rushmore.

For more than four decades, her songs have spanned commercial pop, mainstream Nashville and rootsy bluegrass. A recent episode of the TV talent contest American Idol was devoted exclusively to her songs – an honour previously accorded to the Beatles and Michael Jackson. As an actress, she has performed her “Backwoods Barbie” turn in film comedies such as Nine to Five (1980) and Steel Magnolias (1990). Her demographic appeal even extends to the Tweenie generation, who know her as “Aunt Dolly” in the TV series Hannah Montana.

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Parton’s distinctive brand of southern-fried determination has, with her songcraft, amassed a fortune estimated at between $300m (£186m) and $500m.

In the US, she is almost unique in being loved by both conservatives and liberals. In the last presidential elections, Sarah Palin used “Nine to Five” as campaign song shorthand for her blue-collar individualism (“Tumble out of bed and stumble to the kitchen./Pour myself a cup of ambition”), while thousands wearing matching red T-shirts descend on Dollywood for an annual “Gay Day”.

The Pigeon Forge Dolly Parton Dixie Stampede Dinner Attraction is the first of a Wild West revue franchise that Parton has opened across the southern states. Inside, a rhinestone-clad, mahogany-tanned performer rides two horses at once and hangs off one stirrup with her hair almost touching the sawdust. Piglets race round an obstacle course; children chase chickens; a feast of cold sweet tea, buttery corn on the cob and a whole rotisserie chicken (per diner) has to be torn apart with fingers dripping in grease.

If the eating is messy, the history on display has been cleansed of all complexity. A Charlton-Heston-as-God-style narration echoes through the arena, “It was our never-ending quest for freedom that led us all in to the west.” Some highly buffed longhorn cattle are herded through the sawdust. Minutes later, the columns of a plantation porch emerge from the side of the arena. Chalk-white southern belles with parasols saunter in a circle. There is no mention of slavery or the clearance of native Americans. As the riders take a final bow, Parton appears on a video screen and launches into “Color Me America” – a muscular torch song she wrote in the wake of 9/11. The audience stand and wave their $2 miniature flags as she sings.

Parton is not the first country star to mythologise herself through a visitor attraction – Johnny Cash opened up the “House of Cash” museum in the late 1960s. But in 1986, when she bought into the Silver Dollar City theme park with the existing owners, the Herschend Family Entertainment Corporation, and rebranded it “Dollywood”, her ambition was typically inflated. Soon after, she told reporters she wanted be a “female Walt Disney”.

This is typical of Parton’s fighting talk but Dollywood is, with 2.5m visitors a year, now the most popular theme park in the south outside of Florida. Its 40 shops are vast emporiums of merchandise – Dolly’s Dixie Fixin’s southern cookbook, huge lacy pillow dolls, clubbers’ T-shirts and a whole range of clothing emblazoned with “Dolly for President ’08”.

In her memoirs, Parton wrote that she wanted Dollywood to evoke the feeling she had as a child when the “county fair came to town”. This apple-pie wholesomeness might surprise some of her loucher fans – the park is also alcohol-free and has its own white clapboard church that holds services three times a week. Regulations stipulate, without irony, that women must avoid exposing too much cleavage by buttoning their dresses “at least two-thirds of the way up from the waist”.

Many of the crowd – overwhelmingly white, working class and ageing – are season-pass holders from southern states, explaining Dollywood’s reputation as a kind of Redneck Disneyland. But the park does attract a wider range of visitors. When I visit, a group of 200 African-American teenagers from Mississippi, here on a church trip, are shooting baskets in the fairground.

Cheryl Tobin has made a one-and-a-half-hour drive to Dollywood after finding out, from fan websites, that Parton will be appearing at the park today. “I’ve enjoyed her music from the time she started. The whole family has met her and had their picture taken with her. She’s stayed close to her roots.”

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Indeed, in Pigeon Forge, Parton is the nearest living thing to Elvis. She is also the town’s biggest employer, with 3,000 on Dollywood’s payroll, and acts as a kind of fairy godmother for the region. In 1996, she began a scheme to promote reading in poor and rural Sevier County, where she grew up, by providing free books to every child below the age of five – regardless of their financial circumstances.

Parton appears several times a year at Dollywood and she takes her ceremonial role as unofficial Queen of the South seriously. For these official visits she has, like a head of state, a tightly organised schedule of flesh-pressing: today she is giving out educational awards to teachers and a group of prom-age high-school kids. Like a presidential candidate greeting her supporters, she bounds on to a podium in the centre of the park simultaneously waving, pointing and whispering at people somewhere in the middle distance.

Her tiny legs look as though they might struggle to support the swollen chest and tumbling mane above. The smouldering southern beauty of the “Jolene” era has been swept into something more angular. But, with a shimmering green jacket, cherry-red nails and face powdered moonshine-white, she still looks, at 63, like no one else.

At one minute to the hour appointed for our meeting (Parton is renowned for her punctuality), I hear her swooping southern voice high above a rumble of male assistants. I’ve been waiting in her windowless Dollywood dressing room surrounded by 40 years’ worth of framed album covers, thick carpets and artificial flowers: it’s the only place in the park where she can conduct interviews without being spotted by fans.

Within moments, she is prodding me and dousing me with southern charm. “Maa, you look nice. You must have been hot walking round the park. Better to look good than to feel good, that’s what I always say.” She insists on posing for a back-to-back photo (she’s on her fifth costume change of the day) to show off our matching pinstripes. It is, I suspect, a practised shock-and-awe technique worked on the press.

As she perches next to me on the sofa, I ask whether Dollywood’s unashamed celebration of the south is her way of countering those who think it is all “white trash”. “We do have our share of white trash and trailer trash,” she says, “but we don’t like it when people act like that’s all we are. I’m a very country girl in accent and nature – but I think I can just fit myself right in with the best of them wherever I go.”

Is the camp, cartoon Dolly a character that she has invented? “Whenever I dress up it comes from a very serious place. This is how I think I look best. People would say, ‘You need to change your image or you are not going to be taken that serious.’ But I thought, ‘You know, this is my journey.’ I took my work more seriously than I took myself. People would look at me and think: ‘God. What is that? What would possess a person to look like that?’ My hair is so big a little family of pygmies could live under there. If I have any magic at all, it is that I look totally artificial but I am totally real.”

I had assumed that Parton’s Christianity was, as much as anything, a cultural legacy of growing up in the south and a career-necessity for a country singer. But she talks with sincerity when she explains:

“My lucky charm was God and I always had a great relationship with Him. I would be afraid to be arrogant about it because I’d be afraid that God would take it away from me.”

When writing an album, she takes herself off to a cabin in the mountains, first owned by her great-grandfather, and fasts for weeks at a time to unleash creativity. There are chapels at her homes in Nashville and LA where, she says, life takes on an almost monastic rhythm. “I get up way before dawn, usually; I have my coffee, do my spiritual readings and go over my paperwork. Sometimes I get real creative when the whole world is quiet and still. That’s my God-time. I’m in a space that nobody else can occupy but me.”

Despite this spiritual side, there are parts of her life that would, at least according to the hellfire sermons of her preacher grandfather, see her sail close to damnation. She has hinted in interviews, though never confirmed, that her 43-year marriage is open. At the end of her autobiography she supplies an appendix in which she conducts a Q&A with herself. “Have you ever cheated on [husband] Carl Dean?” she asks. “That’s for me to know and Carl Dean to find out,” she replies.

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Though the truth may be more prosaic, Parton is keen to project a controlled bawdiness; she recently told journalists that when she has sex with her husband, she substitutes him in her mind with the country star Keith Urban.

She’s unusually candid about her sessions under the scalpel: “I’ve never denied it. If you’re going to do it, get a good doctor.” However, dealing with questions about whether she is in favour of gay marriage, she is as careful as if she were carrying a Ming vase across a slippery floor.

“We are supposed to love each other. And people are going to love whoever they love,” she says with some froideur: “But I don’t go round preaching it. I don’t like people even asking me questions about what I feel about this or that. I can see what happens to other artists. You can destroy a whole career. So you’d better just keep your damn mouth shut if you are smart.”

“Too many people appreciate Dollywood ironically,” according to Ned Flanders, Homer Simpson’s irritatingly devout Evangelical neighbour. We are meant to laugh at this line but, as a visitor expecting a kitsch but empty celebration of cleavage, drag-queens and glitter, I think he might have a point. For all its flag-waving, the full-throated celebration of southern life does capture something that is inspiring about America and goes beyond the God-and-guns clichés.

I catch up with Duane Gordon, who in his spare time runs the fan-site Dollymania, as he waits for Parton’s parade through the park in a vintage car. I ask him about his favourite track. “Coat of Many Colors,” he says without having to think. “I grew up poor – and that song is about going to school with patches on your britches. It’s a real source of strength for a lot of people who had difficult circumstances in their childhood or if they get picked on.”

Liberal or conservative, gay or straight, Parton’s fans are moved by her tale of poverty and survival. As visitors stand in line in the punishing southern heat to peer into Dollywood’s replica of the tiny cabin in which she spent her dirt-poor childhood, it feels almost as if they are communing with the American dream. They stare at the old newspaper lining the walls, patchwork quilts and iron pans, which seem to belong more to the 1840s than the 1940s, as if they will give up some secrets as to how Parton got from there to here.

Parton will play to anyone who wants to come to her county fair, as long as the turnstiles are busy. For even she hasn’t made up her mind about whether she wants to be remembered as a timeless songwriter of great country ballads or a sequinned showbiz ham. “I love to sing the songs I write. But, a hundred years from now, I want them to say: ‘Damn, doesn’t she look good for her age.’”