NH is one of my favorite states. I was actually living in Nashua NH when I started keeping Kosher many years ago. (I’m now in Israel)
There is a Chabad in Manchester, And there may be a bungalo colony up in the north of the state somewhere. I think I heard about a kosher cafeteria at Dartmouth college in Hanover, but I have no information on it at all. Past that your going to have to bring stuff with you. Or of course you can get some basics at most supermarkets.