If you’re going to gunstock you should hike/ski/snowshoe around there. Should still be possible especially early in March. That’s the only reason people go to that area as a tourist.

On your way to Boston, stop in Portsmouth. I don’t know why no one else is saying that. It’s NH’s most charming (small) city with the best food and shopping. Also on the coast so you can go from seeing the mountains to the very small coastline which is pretty! The drive from Portsmouth to Boston is easy.