Probably, it would not be necessary to drive in SF itself as public transport are pretty convenient. Legs can probably bring you around. Or another option would be to buy a ticket which allows you to transport yourself around in their famous "cable car" and/or bus (
http://www.sfcablecar.com/riders.html) Get the passport on the first day and be done with it! :thumbsup:
Its a nice place. Monterey Bay / 17 mile drive and Carmel are beautiful places. I took a bus trip when I was there in May. Pretty worth it and save me from the driving.
Parking is problematic in SF itself as there are MANY slopes and parallel parking for most of them except in the "multi storey car park".
Miss that place (especially chinatown food! which is tasty since I have not tasted Singapore's food for a while.......). Need to find time to drive up the scenic route to SF. Am currently in San Diego though and it will take quite some time to do the drive up!
Advise, bring/buy moisturizers and Sun block. The weather is dry over here and the sun is "hurtful" even though it will seem mild. In December, it might be cold in SF, so prepare warm clothings for the little ones especially.
Good luck and enjoy the California Tour!