I remember driving by Alligator Back on my way down the Parkway from Roanoke and wishing I had time to stop. A great add, it looks like an interesting spot to explore. Ice Rock is a cool area along the parkway just to the north. I've heard they get some crazy ice along that section during the winter.
Next time I go, I'm going to scramble down into the valley along the formation. I don't think it's technical. Maybe class III.