It's great to be spoiled for choice! Hopefully you have the Catskill map set for reference when reading this (and backpacking gear in general)-
One loop that comes to mind is an 18-miler (approx.) starting at the northern part of the Escarpment Trail and going over the Blackhead Range. It is only 18 miles but you get a good long climb up Wyndham and up Blackhead Mtn, then over Black Head and Thomas Cole Mtns. There is a bit of a road walk involved at the end(about 3.4mi) going through the resurrected town of Maplecrest but otherwise you are in the woods with many great viewpoints opening up along the way. The trailhead is at Peck Road, near Maplecrest. There is a shelter on the Batavia Kill
This link shows the area:

Hope this helps. If I look at the maps I can come up with others
Sent from my iPad.