Years ago, my company had an office in Foster City and then in San Mateo. I kept a bike there for use when I visited. (Telecommuting before it was fashionable.) I mostly did commuting and running errands, so I might not be so helpful in avoiding busy streets. (For fun, it's worth seeing the mansions in Burlingame and Woodside. And biking to Half Moon Bay was pretty standard.) However, some of my fondest memories are my weekend bike tours, in particular two of them. The first was taking CalTrain to San Francisco I rode in a few times; it was doable), biking across the Bay Bridge, then through San Rafael, and taking the Larkspur ferry back to San Francisco. Gorgeous views throughout. The second involved taking CalTrain to its farthest south station, Gilroy. (Trains only run during rush hours on the weekdays, but biking from the south of San Jose isn't bad. And if you haven't seen the bike accommodations on CalTrain, it's worth the trip.) I biked to Salinas, saw some Steinbeck sites, and stayed the night. The next day I headed to the coast and biked to Santa Cruz, stayed the night. To return, I started biking up and over the mountain on Rte 17, but I decided that was suicidal, in more ways than one. There was a bus that goes over the mountain that had a bike rack for two bikes on the front. When the bus pulled up, alas, both bike places were in use, but the driver let me bring the bike on the bus! I got off in Scotts Valley to visit a co-worker, but later continued into Los Gatos, taking lovely suburban streets back to some CalTrain station or other.