[FlyFish]

Vermont has no licensing requirements of any kind, so that one's easy. Maine requires a license for concealed carry - you can open carry without it, but I'd really recommend getting the license, and you need it to transport the handgun in a vehicle anyway. It's relatively painless to get a Maine non-resident license, particularly if (as I assume) you already have a Mass LTC.

Of course, that doesn't necessarily mean you can just walk out into the woods and shoot, even when properly licensed, so check with the appropriate state agencies on that part.

ETA: Note that Maine will not honor a resident Mass LTC, nor will it honor a non-resident NH permit. New Hampshire will not honor a non-resident Maine permit.