Stop by Santa Cruz for at least a day, it's 45 min south of San Jose and it's a completely different world, lol.
Here are some places around there to check out:
If it's not raining
Henry Cowell State Park : Humongous redwood trees, hiking trails, river.
Nisene Marks:
More redwood trees, hiking trails, ocean views.
In Santa Cruz there's the boardwalk, downtown and its street performers, breweries, coffeeshops, the UCSC campus, etc. There's a couple of restaurants on highway 1, in Davenport (north of Santa Cruz)
You guys could also stop by the Monterey Bay Aquarium, it's 30 min south of SC.
Sometimes there's shows in Big Sur (south of Santa Cruz), check this out:
http://folkyeah.com/
From there you could go to San Luis Obispo and stop by Hearst Castle. Highway 1 is a nice drive, very scenic. From SLO you can go back up north, inland, to Fresno.
SJ-SF-HW 1 TO SC-SLO-FRESNO would be a nice route.
Man, I should be a tour guide. Have fun!