If you really want to secede, raise an army.
True...towns and states usually talk about secession because they feel they're being taken advantage of by the larger entity from which they're seceding...and those doing the taking are never willing to just give up their advantage
Killington is in the middle of Vermont, halfway between NH and NY (a few miles east of Rutland and a few miles NW of Plymouth Notch, Calvin Coolidge's birthplace). There's no way it's going to be handed over to New Hampshire.
I recall when Block Island got fed up with the government of Rhode Island and the state of Colorado offered to annex it...would have given Colorado a seacoast.