Holy shift knob, Batman. I've been to, lessee, Watkins Glen, Lime Rock, Laguna Seca, VIR, Road Atlanta and Road America. However, there IS a track in New Hampfordshire known variously over the years as Loudon and/or New Hampshire Speedway for the roundy round crowd. I had a friend who used to crew for a fellow at Loudon, but I have never actually attended an event there.
Still, its not that far up the road from here and so one might assume that I have been there even though I have not.
The only other one I can think of in my area is Thompson Speedway, but they have never had a road course there (except for karts and such.)
So, after all that backing and forthing, I will boldly guess: whatever the name back then was for the racetrack in Loudon, NH.!