The San Francisco Chronicle suggests camping trips by bike and recommends a few nearby bikeable destinations.
The story mentions bike trailers are available for free use for members of the San Francisco Bicycle Coalition, which I didn’t know.
It also mentions bike-and-hike spots, which I do know about. The journalists suggests reservations for your bike camping spots, which, as far as I know, is not possible, at least for California state parks. There are typically one or two bike-camping spots that are available first come / first serve. Whenever a bike camper shows up and there are no available spots, the early bird has been willing to share with the late comer from what I’ve heard. Note that bike camping spots are smaller (and less expensive) than drive-in spots for the California state parks with bike camping areas. State budget cuts have closed several parks and campgrounds or reduced the services available, so please contact the campground ahead of time to ensure camping is still available!
A handy tip about Big Basin State Park: You can bike a few miles up Waddel Creek from Highway 1 to access what are technically ‘backcountry’ sites within Big Basin along the Skyline to the Sea trail. Reservations are required for the Waddel Creek primitive sites. You can even take a Santa Cruz Metro bus part of the way if you don’t feel like biking the entire distance while hauling camping gear.