I've recently discovered Mountain Dogs in Plastow NH (which is closer than you might think) on the web, but havent gone up there yet.
THere is a guy that does tuning, I think mostly for the many high school racers at Bradford in Haverhill -- I forget his name, but he has an arrangement with Mtn Dogs and is mentioned on their site. I have no idea if he works alone or has or needs helpers, but it's something to check out.
Ski Haus in Salem NH is still there, the one in WIlmington closed when they lost their lease (a new assisted living place is going up there). There are Ski Markets (a mass-market chain) in Danvers, one at the 128-93 intersection (Woburn?), many others - none particularly close. There is a place called Sport Shack or something like that on Main St in Wakefield -- looks more Snowboard and skateboard oriented.
There was a Buchika's in Andover for awhile, but it is gone (now a Learning Express).
I don't know if you have a car -- if not, none of these are apt to be workable.