Stayed in Site 47 for four nights.  Yes, Sheep Bridge road is washboard bumpy.  Yes, spur roads off of Sheep Bridge Rd can be challenging but we managed quite easily with a Ford F250 towing a 27' travel trailer.  For #47 and #48 you have to cross a pretty nasty wash. Highly recommend the BLM map for this area which accurately shows places you are allowed to stay.  Lots of signs showing "camping in designated sites only" but didn't see anyone enforcing it.  Many campers disregarded rule.  Site 47 was big enough for at least 3 large rigs.  Others around it were quite small.  1-2 bars with Verizon.