In the +20 mile range"
Deam Wilderness - about 25 miles of loop options, lots of horse trails
Knobstone Trail - 50 miles, quite hilly, would need a shuttle
Red River Gorge - Many miles and loop options
Big South Fork RA - Again, lots of nice loop options
Tennessee/NC AT - there are several guys who will shuttle you for a reasonable amount. The Roan mountain/balds area is nice
Let me know if you need more details.