Welcome to overcrowded California...camsejach.
Family-friendly means for a weekend or two. Otherwise we have entire third-world countries camp/living in our State, Federal and private campgrounds. Sorry that sounds harsh.
The San Francisco Bay area is busy, crowded, pricey and a VERY popular vacation destination. May have a better luck if you expand your search area east...and commute.
There is a nice, newer RV park in the Patterson area, just off I-5, that folks were longer-term living and using hiway 130 to commute into the Bay area. Bit out of the way, but a possibility. Kit Fox RV park.
Read the reviews on this site. If cable TV is critical to keep your gang entertained...this place may not work. Sat TV and cel service is great and the community is healthy and growing.
Recommend you book a month just to insure it fits your needs...
Once winter has passed, and the snow-birds have all gone home...the socio/economic population that 'camps' for months on end changes dramatically. Fact of life, at least here in sunny, southern California.