Rip Tide and Slugonar gave you some great advice on where to go.
These links might also be helpful:
Want to Tangle With a Toothy Terror? Go Pike Fishing -- N.H. Fish and Game
And at the bottom of this link: Fishing in New Hampshire - N.H. Fish and Game
You'll see additional links under "Suggested Fishing Locations" for
Southeast NH/Merrimack Valley
Monadnock Region/Southwest NH
Great North Woods
Each of the links has a listing of "best bets" for different species, including pike (except for Southeast/Merrimack valley which doesn't have any recommendations for pike.
You might want to ask questions about pike gear and tactics etc in the warm water forum --- we have a bunch of guys like "Diver Dan", "Rmooney", and several others that target them, and "Afton Angler" and an excellent musky guide also checks in from time to time, but they are all out of the NE area so may not see your questions. We have a lot of folks in Canada and Europe that target them too, so you'll get a lot of good feedback.
I know some guys use stuff like Tyger Wire as a bite tippet which is a knot-able wire, but others swear by just a short section of heavy mono tippet. But the only pike I've ever caught was by accident while fishing for steelhead so I'm no expert. (I was targeting steelhead as they started to stack up before they ran up a river and a pike whacked the hell out of a streamer and was lucky enough to land it on just 8lb mono tippet.)
But try the warmwater forum--- good luck-- and be sure to show pics!