Great loop! I ran it clockwise starting at the North Windham parking lot - so Nipmuck->Natchaug->Airline. The Nipmuck trail was in great shape and is well-traveled. I noticed my tracks deviated a bit from the GPX around mile 5 - I was following the Nipmuck the whole way through there, and it's pretty clearly blazed - so perhaps the trail has moved a bit over the years. The Natchaug was less traveled and had a lot more leaves down in spots, so it was slower going, also I got kind of lazy in some spots there. Finishing up on the Airline trail was great, it is a steady downhill and as smooth and non-technical as it gets around here.
Ran unsupported with 1.5L of tailwind and refilled in the numerous rivers along the way. It's been pretty wet here so finding water was no problem at all.