Welcome to California! You'll find that although there are quite a few parking restrictions everywhere in the state, the level of enforcement varies widely. Generally, the closer you are to the coastline and the higher the population density, the less slack you can expect.
Generally, law enforcement is aware of the parking issues with motor homes. If you make the mistake of parking in a "hot zone" you can expect to be contacted by law enforcement shortly and asked to move. If that happens, politely/respectfully ask the officer where you CAN legally park. Then, don't make a habit of using the same place too often. Discretion is the key. Hint: most officers patrol specific areas on a regular schedule and they don't regularly discuss non-events with other officers. Eyesores are memorable events.
Park and Ride, Freeway Rest Areas, Amtrak/Metrolink Train Stations, Walmarts (less everyday), Truckstops, etc., are a few places to try.
Chum lee