My daughter and I visited California for spring break. Aside from a few rides from friends and family, we took transit the entire week. The San Francisco Bay Area has a terrific website, Transit 511, that makes it easy to plot your travels by transit.
After flying to Oakland, we took the airport shuttle and BART to San Francisco, where my brother picked us up at the 16th & Mission subway station. The next few days, we mostly used the SF bus and trolley systems to get around, including the new Muni "T" line that is linking key San Francisco areas and adding economic development potential to some of the city's poorer neighborhoods.
Midweek, we headed down the coast to the Point Montara Lighthouse Hostel. (The view above was the one from our window!) We got there by taking Caltrain to San Mateo, then the 294 samTrans bus. We also took the latter to Half Moon Bay and back one night for dinner. When it was time to head home, we took the 294 to Pacifica, the samTrans 110 bus to Daly City, then BART and AirBART back to Oakland Airport.
The Bay Area's transit systems seem extremely well-used and mostly well-loved. My biggest beef was a sign at the Powell Street Muni station downtown that seemed to show which lines served which stations. On closer inspection, I saw the sign was actually describing transfer points at those stations.
It's always a little confusing to navigate in a city you don't know well, especially one served by multiple bus and rail lines. But we found that transit personnel and local transit users (and my brother-in-law, Kevin) unfailingly pointed us in the right direction. As we fretted about finding the right side of the street for our bus in suburban San Mateo County, my daughter asked me why we just didn't rent a car. Three reasons, I said: to save money, to keep one more car off the road, and to have an adventure. We succeeded on all three counts.