That's a great part of California. I lived in SF for a decade and went up there a lot.
If you're into vintage campers (trailers not TCs) you should definitely check out this place in Guerneville. Real nice older guy running it, lots of crazy rare restored units to look at, and he'll talk your ear off (in a good way) about old school RVs.
http://www.rrvintagetrailers.com
Also if you like champagne, Korbel is nearby in Sebastabol and does a great free tour.
Russian river is great for fishing/rafting/canoeing if the water is high enough, and don't miss Armstrong Redwoods Park too for some giant trees.
Have fun!