Point Reyes is a wonderful and easy place to camp. You can backpack, and if you reserve different camping spots on different nights, you can start at one spot and backpack to the next. All the sites are beautiful, and the views are spectacular. At this time of year you could easily sleep under the stars in a lot of them without an issue.
Just be sure to call ahead.
Big Basin in the Santa Cruz mountains (towards Santa Cruz) is also gorgeous, and if you organize your tranposrtation, you can do a cool 1-way backpacking trip (2 night minimum) called “skyline to the sea”. You can also just do a loop. There are plenty of water spots, some nice vistas, and lots of tall redwoods.