Most county parks here in Northern California ban operating an sUAS inside the park area.
If you were on private property and flying over the park, then by most interpretations of the law, you would not be violating any law - as long as you are obeying all FAA regulations (not flying over people not flying over moving vehicles, not operating in an unsafe manner, etc.,).
Do note that MUCH of the SF Bay is in SFO class B airspace from the surface. If you are down by Palo Alto / Newark then you would be outside of surface Class B airspace.
Looking at the sectional chart, I don't see any NATIONALLY regulated parks / preserves in that IMMEDIATE area that you can't fly over. Most of the NOAA-designated no-fly areas are on the coast.
NOTE: I could be wrong on this. I see some blue dots that follow the shoreline on the souternmost parts of the bay, and I am not familiar with these... They are on the shoreline just due east of the Class D airspace for San Carlos SQL. around 122 10 and 37 52. I am clueless as to what those blue dots represent (probably something completely benign).