Lots of small towns that welcome us as boondockers. We park in the plaza, talk to the local police or a tourist office if open and they direct us to a spot or make recommendations. From there, we take a taxi to show us the sites nearby if we feel me might have difficulties with the trailer.
I'm not familiar with the west coast in terms of beaches but we boondock a lot, love it and continue to do it. It's not for everyone and I am not making any recommendations.
That said, we toured the western U.S. and Canada and it requires the same knowledge about where, when and how. Security is a global issue now, it's not concentrated in one spot.
We met lots of nuts this last four months including boondocking forest service and BLM. Boondocking is not for the light-hearted in any country. Be smart, follow your instinct and enjoy beautiful untouched places.
Our most frequest states are Nuevo Leon, Coahuila, San Luis Potosi, Veracruz, Zacatecas, Jalisco, parts of Michoacán, Hidalgo, Queretaro to name a few.