Tom, Trails Road is an abandoned "book road" about an hour west of Philly, just west of the Susquehana River. Mostly mud but with some nice rocky areas that are equivalent to Blue at RC, even a few black obstacles. I haven't got out there but I hear it's a fun time.
Just be careful as the road goes right through a residential area with houses very close in many areas. Stay on the trail and out of the creek, and be respectful of the nearby landowners.
Maybe we should do a run out there this summer.