Although there are indeed a lot of wild boar in California, it is very difficult to get them on public land. They are mostly located on private land and your best bet is to pay a guide to hunt hogs. By the time you make several trips to try for a hog on public land, you will spend what it cost for a guided/private land hog hunt.

Maybe write to Petersen's Hunting and ask an editor. I know they've done articles on hog hunting in California, because I remember reading one about hunting hogs with a .44mag handgun in the northern part of the state.