It sounds like Saw Kill (aka Jockey Hill) might fit the bill. Here's a link to the info on GDC: Jockey Hill
The maps here covers less than 50% of what's in there. There is another section you can enter at Onteora Lake off Rt. 28 where there's free camping. You can do all the trails on that side one day, then drive 15 minutes to the entrance at the cul-de-sac. There's at least 2-3 days worth of riding in there, but if you don't know the area you can get lost easily. The trails are similar to American Standard in Jim Thorpe, lots of embedded rocks and technical. The climbs are steep, but short.
Here's a link to MTBR: Onteora Lake
There's more single track in there than you can shake a stick at.