Heading up that way this weekend, and I never even knew you could get off the 140 at Briceburg (always just drove past w/out looking) and now, having mapped it, I see there are all sorts of Forest Service/fire roads back there.
Bull Creek Road, Ponderosa Way and the Briceburg Road all seem to go all the way through.
I assuming it's mostly just heavy forest, but one never knows.
Thanks!