Some of mine are;
Cycle Oregon’s, which has some of the best services, i.e. showers, transportation of gear from town to town, great food, okay camp sites and great scenery. www.cycleoregon.com
The Olympic rain forest in Washington State, with a stop in Friday Harbor (Puget Sound) and a ferry ride into Vancouver BC and Victoria BC , a memorable ride. Tim Kneeland was the organizer, but it appears he no longer books rides, however, worth a solo.
Death Valley California is by far the most interesting varied scenery, but go supported even in March, h20 is at a premium.
Would like to start this thread to learn from others the rides they have experienced in the South, southwest, and Midwest and of course all places in between.