If you've got a four-wheel-drive or dual-sport motorcycle you can turn off and bump down a dirt road to soak in hot springs, like I did, where I found myself blissfully alone, free to lie naked in the sun like a lizard on a smooth, cool boulder.
http://www.examiner.com/x-15878-SF-Motorcycle-Travel-Examiner~y2009m7d6-Historic-and-Scenic-Highway-395-is-one-of-Californias-best-road-trips