On the way up, definitely stop in San Luis Obispo at Firestone Grill and get a tri-tip sandwich. You can thank me later. You should consider pulling off in Santa Cruz, and taking Hwy 9 up to Hwy 35 (Skyline Blvd) which will bring you along the mountain ridge past Alice's restaurant. Sort of a motorcycle mecca (watch for squids). You can continue on this road much of the way to San Francisco, past Pacifica. Just tons of natural beauty there. This route isn't too much of a detour and you get to experience some of the main popular stuff.
If you're looking for a few hours day ride in the area, it depends what type of riding you like. Wide open sweepers and smooth roads, or tighter goaty stuff. But you pretty much can't go wrong with a ride up to Alice's on Hwy 84, including Pescadero Creek Rd, and then looping back up the coast to SF, or back the way you came.
Hope that helps.