Billy and Patti Romp are pretty sure of one thing: By the time fall rolls around, their kids Ellie, 11, Henry, 8, and Timmy, 3, will know "the United States from sea to shining sea." That's when the Romp family plans to arrive—weather-beaten and leg-weary—in Homer, Alaska. They'll dismount from their used, custom-built, 32-gear bicycle-built-for-four (plus a caboose for Timmy), ending a 5,500-mile ride that began in Shoreham, Vt., the hometown they left on April 1.

The Romps took to the road to complement the kids' home schooling. "Not only are they seeing the whole country," says Patti, 43, an alternative-health practitioner, "they're feeling the whole country."

The traveling geography lesson—the Romps stick mostly to back roads—has taken them to the New York Stock Exchange, Washington, D.C., and a mid-western steel mill, as well as to more national parks and museums than they cm count. And though they packed camping gear, the family usually stays in the homes of people they meet along the way. "We could never repay the kindness we've seen." says Billy, 46. a freelance writer who sells Christmas trees in Manhattan's Greenwich Village each December.

Around the end of July the Romps will ferry to British Columbia, then to Alaska. After completing the last 1,500 miles of their trip, Billy says, they'll buy a pickup truck and tie the bike to the roof for the journey home. Which should make the return trip a relative romp for the Romp relatives.