IMHO, your best bets are along the coast or higher elevations. The coast along CA, OR and WA gets very crowed during summer and California campgrounds can get pretty expensive. There is some wonderful country to explore in the Sierra Nevada Mountains and the Cascades. Parts of US-395 take you into some great country and high enough to avoid a lot of heat. Some of the mountains in Idaho, Montana, Wyoming and South Dakota are well worth visiting. Also spend some time exploring around the Black Hills in South Dakota.
Art
