There is a group at yahoo called Auto Touring that is about classic auto touring and includes auto camping. Experiences, roadside attractions, how-to's, etc. are more than welcome.
US 30 on the Columbia River
Hwy 50 in Nevada - which along with the Columbia Gorge Hwy and Hwy 95 down through Oregon/California are my favorites.
Also CA 89 from the I-5 on through to the end south of Markleeville.