My dad used to visit Dartmouth and drop the family off in Georges Mills. There was a native brookie stream one of the local boys I befriended showed me, they went nuts over hoppers. I drove by it last year on my way to my son's basketball camp in VT, and it was heavily guarded for it's native brookies (reassuredly).
I recall that there were tribs all around the region in particular one that ran into the lake at Sunapee center. It was full of trout and I believe it is open to fishing upstream. I don't think you'll have to dig too hard to find good fishing up there.
If you don't mind the drive, I used to fish Sugar and upper Swift Rivers as well as the Ammonusuc (sp?) which were chock full of trout. The further out you go toward Lisbon and Littleton (to the north) the more naive the trout became. My wife-to-be and I used to camp up there, the area up there holds a lot of good memories for me. Of course two daughters later... camping means hot running water and electricity for hair dryers!
Sorry I can't help you more. Have you thought about calling the Hunter's gang in New Boston?