Ben Nephew posted the route:
The Nehantic Trail is a 13 mile singletrack route in eastern CT from Green Fall Pond in Voluntown to Hopeville Pond State Park in Griswold. It is mostly flat and runnable, with a few small hills and some short technical sections. Road sections are minor and the trail markings are excellent for such a remote trail. Details and maps can be found in the Connecticut Walk Book East.
My out and back on the trail started at Green Fall Pond and turned at route 201. I ran the 26 miles in 3:30:40. It's a great trail, and there are several other options for long trail runs from Green Pond.