I lived in NH for about 12 years. The riding there is great, and it's within reasonable driving distance of the Kingdom Trails. Definitely look them up and take a drive out there.
The winters are cold, probably a little colder than you're used to in Iceland (avg. winter temp doesn't dip a whole lot below freezing there, does it? NH can get a whole lot colder than that). There's good skiing within driving distance, though. All the snow in the winter is beautiful.
Rye is a good indoor park (let me know when you go, it is about 15 minutes from my house). Granite Skate in Nashua is alright. Hopkinton is a good outdoor park. I haven't been in NH long, but my buddy Eric knows every park worth riding and all the super secret digging spots.