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.
"Killington is in the middle of Vermont, halfway between NH and NY"
Yeah, that's why this is just a joke. I don't think NH would want to take a city in the middle of Vermont even if the Vermonters wanted to give it to them. On the other hand, this is the kind of publicity stunt that folks rally behind to make a point.
It's sort of like the Minnesota thing a few years ago where the MN Senator proposed to give a small piece of MN to Canada. Everyone knew it was going no where, which is why he did it. But it gave him some attention and made the locals feel important.
Vermont used to be part of NY. Maybe they could just give Killington and everything south thereof back to NY.