Mine was at Hollister also, on Adobe trail. Very bad crash - we hit heads and my knee hit his fork tube. Would have been fatal with an open face helmet. As it was, it was bad enough.
Since then, I prefer to go far out in the forest. The trails may be two way, but the farther you get from the staging area, the less likely you are to find other riders and quads.
BTW, the guy who hit me was an experienced rider. He was 'freelancing' and going off the marked trails. When he hit the marked trail, he thought he was going the right way. Or so he said in his deposition.