There are plenty of unmarked fire roads to adventure through. Ice House Rd off of highway 50 will take you up to Ice House Lake. If you continue you will hit Union Valley Reservoir and later encountering Loon Lake. Around the loon lake area is where an entrance to the rubicon trail is. I don't advise you to head to that trail head unless you have the rig to do it. Bigger axles or better shafts, gears, lockers, tires, winch....etc. An if you do head that way, have the expectation of breaking something(s).
Jump on Google earth or Gaia GPS and snag some forest service maps. Plan something out!
Sent from my SM-G950U using Tapatalk