If you had time, I would strongly recommend heading north to the Wine Country.
If you base out of Santa Rosa, about 80 miles north of SFO, you will be in the middle of Sonoma County. This arguably the center of the wine producing capital of California.
The Korbel Champagne Winery is an absolute "must see"! Stop in at Healdsburg before you go there and get some fine cheese, sourdough bread, and deli meats first. Buy some bottles of champagne at Korbel after the tour, then drive for 15 minutes and have a picnic in a Redwood forest.
I have spent many vacations wandering around this area with no particular destination in mind.
If I didn't have to work, this is one place I could live quite happily.