There's an exit on I-8 for Pine Valley. If you turn right at the exit the paved road basically ends at a staging area that a lot of bikers use. You can follow that road up and over which eventually takes you to where the Buckman Springs I-8 exit is.
As a heads-up, recently the gates have been closed in that area.
If you travel east past Pine Valley ~10 more minutes or so, you'll get to the Lake Moreno/Buckman Springs exit. Take a right, go straight through the stop sign and travel south ~4-5 miles til you get to the entrance of Corral Canyon/Lake Moreno on the right.
Continue ~4-5 more miles on a windy dirt road til you get to Corral Canyon OHV/Lake Moreno.
You may want to get an Adventure Pass someplace. IE: possibly at the Ranger Station or elsewhere prior to entering the park.
If you go to 4 Corners & park there - you need the Adventure Pass, or for that matter, anywhere you park.
CC has some fun 4 wheeling available depending on which trails you run. Depending on which trails are run, expect body damage, broken parts, roll over etc.