i know hawley/masthope pretty well - up by big bear ski area right and lake lackawaxen.
i have ridden up there on the game lands - man there is so much land up there. there are a lot of trails up there, but most of them for hunting and none of them were hiking/biking specific, so what starts off as a solid trail usually just ended up fading into very sparse trail or forest trail, and i would eventually pick back up on a fireroad that i would stumble across. so my experience was kind of a shot in the dark. sometimes i would get lucky and find some good stuff, sometimes, not so much.
but everytime i would bring the bike up there, i would venture into a new game land and i had fun. its rough riding - as in totally unmaintained - so lots of deadfall or just uncut triail in spots. if you do venture into a game lands for riding, wear lots of bright orange. there are a ton of hunters up there.