If you're on the Peninsula, you likely know all the big climbs. Just focus on getting your climbing form, Old La Honda, Kings Mountain, Alpine in either direction, and my personal favorite, climb Tunitas Creek - it's steep, long, but covered in shade. I used to live in Redwood City, and one day I did Kings Mountain up to Skyline, down Tunitas Creek, down the coast to Pescadero, then up Alpine. I was pretty wiped out. Two major climbs in one day, and you get to stop at the Bike Barn:
like mirage in the middle of nowhere, there it is.
For a good gravel ride simulation, head up to Mill Valley and ride up Tamalpais on the Railroad Grade to the top, and do it on your Eroica bike. Even if you're not doing Eroica, you should do that ride at least once.
Is there a better view? Actually, there is, this is only half way up Railroad Grade...