There is one cheap thing left in California, and that is boat regustration: $10/2years for salt water.
Harbor hopping is possible. 5 days free mooring per harbor, and 6 harbors rince and repeate.
6 x 5 = 30 . O , so 5 days free mooring in each harbor per month.
Sailboat might cost. But I saw one , a 28ft cloumbia for $650.
I am not sure about insurance requirenments for harbor hopping. For docking, yes, about S150 / year.
Campgrounds in California, generally about S35 /night with car.
There is a so called hike and bike, for hikers and bikers $6/night.
One of the trick is to have a van, and a bicycle. Park the van on the street, bike to hike and bike for night.
In lots of towns they do not allow parking RVs on the streets. The trick is to have a van, not an RV.