Wolfgang Werz, a 67-year-old former ski instructor from Tubingen, Germany, leads a group of German and Swiss tourists on a two-week, 2,500-mile Harley Davidson journey along Route 66 from Chicago to Santa Monica. The 'Mother Road,' dubbed by John Steinbeck, turns 100 this year, prompting refurbished motels, diners, and gas stations to prepare for increased tourism. Though no official ticket sales exist, a 2011 Rutgers study estimated $132 million in annual spending, with expectations of higher revenue during the centennial.

International tourists, comprising over one-third of visitors, spend more and stay longer than domestic travelers. Jennifer Brennan of the Fanning 66 Outpost in Cuba, Mo., reported a 50% sales increase this summer, citing strong demand for souvenirs. Peter Fordemann and Katja Weinert each spent about $10,000 to join the tour.

Patrick Tuttle of Visit Joplin noted visitors from 45 countries spent $5.7 million in Joplin last year, largely Route 66 travelers. Mike Cowen in Williams, Ariz., said 60% of his customers are international. Despite economic benefits, some travelers, like those guided by Sam Murray of New Zealand, canceled due to concerns over the U.S. political climate, compounded by a strong dollar and rising travel costs.