If you thought Channel Islands Marina was too big and too close to urban areas, I'm afraid you're not going to have much luck. I don't mean to be rude in any way, but Southern California doesn't have many natural harbors, and even the man made marinas are all near urban or suburban areas. They are all pretty big, too. Even in a place like Newport Beach, which has many smaller private marinas, rather than a large municipal one, has a total of something like 10,000 boats. Long Beach has municipal marinas that are reasonably priced, but it is also a major commercial harbor. Keep looking online and asking around, though, and actually visit some locations if you get the chance. SoCal is a big place, San Diego is a long way from, and quite a bit different than Ventura, for example. It is all great year 'round sailing though!