Montana's Going-to-the-Sun Road might be enough -- at least for your knuckles, which are likely to be squeezed white after winding 50 miles (80.5 kilometers) along the mountainsides of Glacier National Park.
But Glacier is only the first on this national park tour through the Rockies. From the park's southern tip, catch the I-90 for a quick shot into Yellowstone National Park and then Grand Teton National Park, before swinging hard-east along I-80 to Saratoga, Wyo. Wind your way through Rocky Mountain National Park to the town of Estes Park, where the famous hotel from Stephen King's novel "The Shining" overlooks the main street.
From there, it's possible to follow national forests all the way to Santa Fe, N.M.