There is a truck trail in Julian.
http://www.off-road.com/trails-event...ils-53551.html
Its definitely considered novice, I guess, since there's video of a wrx doing it on youtube 😀
Hopefully you're not going alone, you have tires suitable for off road/snow, straps, recovery points, and a plan to get home if you break..
Corral Canyon ohv is a nice ride. There is a large scenic route that goes the perimeter of the park and its a step up, but doable with 4wd. It'll take about 3hrs to do the 14 mile(ish) loop if you go fairly slow and dont want a bunch of scratches.. I did it in about 1.5 hrs in my 1st gen.
(They have been closing the gates out there lately for rain... call first)
Post up pictures of your truck..