Hill, with daughter Gracie, at a fashion show last fall. Photo by: STEVE SANDS / BAUER-GRIFFIN
Tim & Faith: Heart to Heart| Faith Hill, Tim McGraw
"That's not necessarily true," McGraw counters. "Guys are different."

"Then you need to teach them that's what kind of man they need," says Hill.

"Nah," he says, "I need to teach them, 'See? That's the difference between guys and girls!' "

Venus and Mars will have plenty of time to hash out life lessons as the family covers some 20,000 miles in their 45-ft. bus. Like the progression on stage – opening duet, 13 songs for her, two more duets, 11 songs for him (time for her ham sandwich), and four final duets – free time for the kids is carefully planned. In Philadelphia the family visited the Liberty Bell and Betsy Ross's house. At their next stop in Hershey, Pa., Mom took the girls on rollercoasters and water rides at Hersheypark while Dad napped. "She takes the morning," he explains. And in Hershey, the afternoon too. By about 2:30 p.m., Hill was getting tense. "The kids are going, 'We haven't done this or this or this, Mom. You promised. . . .' And in my head I'm going, 'Okay, by now I'm usually getting ready for the show.' I want to do everything," she says. Still, "Days like this can't exist every day."

Not surprisingly, both parents value some time to themselves (two nannies help with the girls). "Sure, we need alone time," says Hill. Says McGraw: "But we get that. We have separate dressing rooms because she's got 36 girls running around doing hair and makeup." ("Thirty-six?!" Hill interjects with mock horror.) He adds, "I like to go to my room and take another nap or watch Bonanza."