Surf - I live in Murrieta, about 30 miles south of Riverside. I'm not too sure what's between us, but the Idyllwild area has some great roads and trails that I'm dying to explore. Not sure if you saw Motorpig77's post, but he's putting together a run to that area for 10/18. You should definitely come along if you can!
Nick - I've been to Santiago peak before, but not in my Xterra. I've seen a couple of your trip reports using Indian Truck Trail. I've been up that way once using ITT, and once using North Main Divide from Ortega Highway. Never have been up from the Bedford Motorway side, although I'd love to give it a try one day. I've also never explored anywhere north of the peak (towards Sierra peak). That's on my short list, too.