The DFG office, (and probably online) you can get the garden variety maps of "where to hunt wild pigs in San Diego". To be brief, the areas are in between Julian and Highway 8, It's straight up and down, usually very thick chaparral everywhere, and you'd better have your Cleveland National Forest Map with you to show you a rough idea of private property boundaries.
Have I hunted for them? Yes. Any pigs? No. Any sign.., maybe, but old.
Any day hunting is better than wishing you were though, so after a full sweaty day, I 'Joined' a casino down the hill and got a free prime rib dinner.
I interviewed Randy Biotta the local biologist in the radio once about 15 years ago, before the current pig Flap. I had heard of pigs in San Diego even back then and asked him about it.
He said Palomar Mt., had a stable population but to get in there they had used horses. I imagine that population still thrives, for a good reason; You'd have to be pretty determined to get in there on foot, get a hog, and get back out.
The only hogs I have personally seen were two piglets by Henshaw. I tried to circle and cut off 'mama', but found only sign. That area has since been "locked up", perhaps illegally, by the Vista Irrigation District.
Good luck! They are there, but no one says 'exactly where'!