If pigs are as prolific in CA as they are in the cental south, farmers will welcome anyone to shooting them. Google image wild hog damage, or something, and see what they do to fields. Farmers absolutely hate them.
Sys, check out the county website. Many counties, around here anyway, have digitized the land records into GIS maps that you can access on line. Some give you a tract number that you can use to call the appropriate county office to get the owners name, and some give you the owners name. Many borrow Google Earth as a background and show you basically everything about the property, info wise. Anyway, get the name of the owner, google the name and give them a call. The commercial properties may say no for insurance reasons, but I bet you will be better received than you think.
Also, I love wild hog. It is fantastic. Black russian boar is my fav meat. It is delish.
Most of the hogs in the wild are not black russian, but some states have a few as well as a decent amt of hybrids from outfitters introducing themn illegally and them breeding w the locals.
Anyway, hog hunting is cheap and relatively easy to get into and I would reccomend it.