I know I'm a little late to the game on here but I find a pair of two way radios invaluable when trying to get into tight spaces.
Also for OHV areas in NorCal, try River Rest Resort in the town of Washington off of HWY 20 near Navada City. The drive down the canyon is a bit harry (make sure and have your exhaust brake on) and the campground is a little tight but it's right on the Yuba river and you can ride right out of the campground, through the main street of town and onto miles of old logging/mining roads.
Eric
Eric