When I first moved here, I joined a bikecamping group that left from SF for Samuel P Taylor park. That was when I realized how much nature I could easily access without getting into a car. Even today, cycling across the Golden Gate Bridge to go to San Anselmo for bread or China Camp for camping is still a beloved activity. The multimodal nature of transit is a blessing (I would then just head back to Larkspur and take a ferry back. Or put my bike in a bus from San Rafael)
Tofay, I am in a car as I’m going much much further. But the small weekend trips for birding or whale watching or mushroom foraying keep me happy here.
If you hike or bike, you can get a camp site quite easily even without a reservation