At the Valley Motel, somewhere east of Manistique, on Michigan's Northern Peninsula, the peripatetic Jane Kansas talked Dave, the proprietor, into a cut rate of $30 for this beauty. Later, Dave and his twin daughters showed up with a dinner of steak, real fries, shrimp, rice, cheese, and olives. "We thought on your walk you might not get many home cooked meals," Dave explained. Before bedtime, the girls returned with a banana and a doughnut for dessert. To the people Jane encounters on her epic walk across the American Midwest, she must seem the oddest of strangers: a short, sunburned woman in late middle age,...