From PEOPLE Magazine Click to enlarge
Um, where are we?" Carrie Underwood asks no one in particular as she gazes out the window at a landscape of brown grass and nondescript office buildings. "No, seriously. Where are we?" she asks again. The answer is Windsor, Ont. - a Canadian suburb just outside Detroit—but the country superstar can be forgiven the momentary confusion: Windsor is the whopping 82nd stop on her smash Blown Away tour, which has kept her on the road for the better part of eight months.

She did get a two-day reprieve for her 30th birthday on March 10, which she planned to celebrate at home in Nashville with her husband, NHL star Mike Fisher. "I was like, 'I only have 48 hours. I want to do my laundry and go out to dinner,'" she recalls, cuddling up against the Canadian chill in a well-worn men's sweatshirt bearing Fisher's team logo, the Nashville Predators. "But Mike got the flu, so I ended up eating vegan pizza. By myself. I was like, 'I'm not mad at you. I do not want you going anywhere, because I know you feel awful. But I do expect a redo!'"

The rain check might need to wait a while. Still crisscrossing the U.S. by tour bus through the end of May, the diminutive 5'3" singer—in person her famous blonde mane appears almost bigger than she is—continues to reign as one of the most successful American Idol alums ever. Her new single "Two Black Cadillacs" recently became her 17th No. 1 hit; she returned to her "alma mater," as she calls Idol, to perform on April 4; and she's up for two awards, including Album of the Year, at the Academy of Country Music Awards on April 7. She rolls her eyes at her squeaky-clean image ("so boring!"), but she's still the kind of star next door who does her own makeup on tour and prizes her Harris Teeter "Very Important Customer" grocery discount card. ("I'm excited when they say, 'You saved $11.82 today!'") "She's the furthest thing from a diva there is," says her friend, singer Brad Paisley. "Carrie doesn't take herself too seriously." As her star has risen, "she's more confident, and she understands she has to stay true to herself in order to maintain some sense of normalcy," says her lifelong friend Jordan Vandiver. "She's still a small-town girl, and that upbringing comes out."

Still, even Underwood is a little amazed when she looks back on her journey from Checotah, Okla., farm girl to six-time Grammy winner in just eight years. "So much has happened in my life; it's mind-boggling," she says. "It's been crazy and fun, and there's nothing about it that I regret. And I met the man I married."

As her third wedding anniversary approaches in July, Underwood has learned plenty about the challenges of maintaining a long-distance, two-career marriage. Sometimes "I feel like I'm not able to be a good friend or a good family member or a good wife, because, y'know, I'm not there," she says. The Ontario-reared Fisher, 32, shuttles between their Nashville home base and away games during hockey season. "Everybody else always has dates to things, and Mike's flying solo," she says. "I'll come home and there's no food in the refrigerator. It makes me feel bad sometimes that I'm not there to take care of him." She gets an emotional assist on the road from her beloved pups Ace, a rat terrier, and Penny, a dachshund mix. "I couldn't stand to be away from them for that long," she says of bringing them aboard the bus. "Mike complains. He's like, 'How do you think I feel?'"

At the same time, "he knows [performing] is what I love, and he completely supports me in it, as I do him," she says. "But if Mike ever told me he needed me to quit, I'd quit. When you make that promise to somebody, and you stand before God and your family and friends, you've got to do everything that you possibly can to make that work."

So they make the most of the time they can carve out together, even if dates are often at Subway. "We called it 'our place' when we were first dating!" says Underwood. The singer—who has maintained a 20-lb. weight loss since her Idol debut at 21—eats mostly vegan food, so she gets "the Veggie Delite, and he can get his footlong. Even when he's like, 'I'm so out of shape,' he still has a six-pack," she says. Meanwhile she hired a trainer to make sure she stays in shape on tour. "It's more motivation to actually get up and work out. Having Mike there - I want to be a hot wife!" When she walks a red carpet, Fisher texts her about how sexy she looks. She texts back; "Wish you were here!"

Underwood says the biggest key to their relationship is "trust I don't ever have to think about, 'What's he doing? Who's he with?'" says the singer, who previously dated Dallas Cowboys quarterback Tony Romo and Gossip Girl star Chace Crawford. "I've never considered myself the crazy girlfriend type. But there have been a couple of guys who made me crazy, and it's just because I didn't trust them. With Mike, everything was just so easy." Although they only dated for a year before getting engaged—and tied the knot just seven months later—"it was like, 'This is The One,' as cheesy as that sounds."

When they're home together, despite nightly thermostat wars - "Mike is like a thousand degrees in bed!"—the pair make their marriage a "team effort," often hosting friends for wine-and-grill nights. She and Fisher share laundry and cooking duties. "It'll never be just Mom in the kitchen at our house," she says. "I like that I feel like even when we have kids, it'll still be a family affair."

Until recently, "I've never been the kind to think about kids," Underwood adds. "But I know Mike would be an incredible dad. Not that it's gonna happen any time soon!" Given their hectic schedules, "it would be much better if at least one of us were in a more stable situation" before tackling parenthood. Even when Fisher retires from hockey, "I still hope he has a job [that keeps him busy]," she says. If he were at home all the time, "he wouldn't be happy, and that would probably make me miserable. I think we both kind of enjoy missing each other."

Still, she does look forward to the day when they can settle into the family-friendly home they are building outside Nashville. "I want cows and pigs and goats and chickens," she says. "My husband grew up the same way I did, and we wouldn't trade it for the world. I really want my 30s to be all about my family and my friends and the real legacies that hopefully we'll all be able to leave behind. I know when we do have kids, it's gonna be wonderful. I'm excited about our new house and our farm. I dream about those things."