I think the riding out here is much less stressful than riding out east in the new york metro area (I felt drivers were more aggressive in the east coast). There are bike lanes on most roads here, and a lot of signs on the roads say "riders can use the full lane" or "give 3 feet when passing." I think the cars are used to seeing lots of bikes in silicon valley.
Even the roads where people may be driving fast in the mountains, the shoulders are wide and the roads are relatively wide. I ride about 12 miles a day with my kid on a gravel bike (and he's in a seat behind me) and love riding in the bike lanes. The suburbs here are pretty and the roads are very smooth. Riding through Atherton is like riding in Greenwich, CT but with nicer weather.
That said, I always feel more comfortable early in the morning when there are less cars on the road.