The Buffalo River Trail runs about 37 miles from Boxley to Pruitt, Arkansas, though the Buffalo River National Forest.

The Catawba Triple Crown is a 35 mile loop in SW Virginia that goes around the small town of Catawba using the AT on Catawba/Tinker mountains and the North Mountain trail on North Mountain.  It goes past the highly photographed McAfee Knob, the iconic Dragon's Tooth rock formation, and Tinker Cliffs. There is a Strava segment for the effort (just happens to be CCW and starting at the Dragon's Tooth parking): 

https://www.strava.com/segments/10348624?filter=overall

The Allegheny Trail runs from the West Virginia-Pennsylvania border near Bruceton Mills to the Appalachian Trail on Peters Mountain, north of Pearisburg, Virginia. The trail appears to be under construction, and will eventually be 330 miles long, but about 20 miles are yet to be completed (as of 2017).

Here's what GORP says about the 76-mile long Foothills Trail: