RidewithGPS has a great library of rides that you can load onto your bike computer and will give you turn by turn instructions. China Camp/Tiburon is great--especially if you don't want too much climbing but get some great scenic views of the bay and some nice food in Tiburon.
Railroad grade up Mt. Tam is nice too, the only thing to watch out for is traffic as it can get congested during the weekends. I usually descend the railroad grade and go up the fire road (very doable with any bike, but I recommend 30 mm tires or wider). I can give you GPS data on that ride too (if desired)--the special treat in addition to the views is a stop at the "pancake place" as I call it. West point inn. Here's a writeup from a hiker, but you can see all the bikes there. (No road bikes pictured, but there is a kiddy Mtn bike, so you know it can't be too hard :).)
Toshi in Oakland, CA