Blue Ridge Parkway —Appalachians.

The Blue Ridge Parkway is America's most-visited national park unit and its greatest motorcycle touring road. Stretching 469 miles from Shenandoah to the Great Smoky Mountains, it stays between 2,000 and 6,000 ft of elevation through rolling hardwood ridgelines, stone-arch overlooks, and meadows that are purple with rhododendron in June. A 45 mph speed limit enforced by rangers keeps it contemplative. There is no commercial traffic, no intersections, no traffic lights.