I probably ought to write a description for this, but I'm not quite sure what trail it refers to, since the nearest thing to a loop is much longer. Buttermilk falls lies at the base of a ridge, 2 miles west and 1000 feet below the Appalachian Trail. I normally hike there from a parking area at Crater Lake or closer to Millbrook Village, but on this day, I took the rough, one-lane woods road from Flat Brook the base of the falls and hiked up to the AT and along toward Rattlesnake Mountain and back.
Buttermilk Falls is impressive when there's enough flow, and today was good. The Mountain Laurel and strawberries are long gone, but the Rhododendron is blooming along the brook and the entire ridge is covered with newly-ripe blueberries. It was a rare bear-free day, and there weren't many people either. Just a few miles down the trail is probably the busiest section of the whole AT, but this little bit isn't nearly as popular.
I put up a few pics and a GPS track.
EDIT: I found a description of the actual purported loop. As I suspected, the distance is a bit longer (9.3 miles), and half of it is bushwhack (split evenly between true bushwhack and travel on abandoned trails). I like the out-and-back version better, since it has more views than plowing through the woods along the base of a ridge.