I have heard nice things about the 3-day 100, which is a big one for ECTRA. However, it always falls on the same weekend as an AERC-sanctioned ride, so I have never made it there myself.
The GHMA 50 never seems to work for my schedule either, as Fort Valley is the following weekend (and much less travel distance).
I hope to get up that way to the Moonlight in Vermont ride in July and possibly the Northeast Challenge (Maine) in August. Certainly gorgeous places to ride!!
There is no joy equal to that found on the back of a horse.