Almost all the San Diego stuff is East county and the desert. There is a place off the 8 calle caral canyon, mainly fire roads and a few trails. Then there is Borrego. Ocotill0 wells and coyote canyon. I did the Otay truck trail last week. Really no challenge unless you like driving a road anout 2 feet wider than your truck with a rock wall on one side and a shear drop off the other. It runs about 13 miles from dulzura to the border. The border patrol use it most. Its on Federal BLM land so some go out there for target shooting toowhere in san diego do you go?
The one that I know of is off the 79 by Auanga called High Point Truck Trail. Have not done it, but was told it's fairly easy. I would wait till it cools down a bit though. I have been wanting to do that trail, so maybe one early am we can hit it up. I want to wait till I am lifted, but I am still waiting on the rear leafs to ship.I'm in North Escondido and I'm trying to find trails over or around Temecula to drive on but haven't found much yet.