A lot of easy trails within a couple of hours of San Diego. Pine Valley you could do alone, don't really need 4wd for most of it, not sure if you can Camp. Some of the Barrago Springs trails are mostly sand, last time I was out there in Jul/Aug people were camping out. Though it was 103 at 1130pm, so not sure if that time of year is the time to be camping. A few groups on FB in the area. SDJC does runs every so often, they say that the trails are hard but I have yet to see anything to crazy with them.