It's about 350 miles round trip from the Bay Area. Starting in San Jose, heading to Hollister, then taking 25 down to San Miguel. Lots of things to see on the way. Pinnacles, fault line, and you can even go back home up the coast via 1.
25 is the lonelist road with lots of high speed sections mixed with a few twisties.

Here's a view of the San Andreas fault:
http://www.youtube.com/watch?v=GG6Ss9iJkbA