We live in Burlington, VT with our 2011 22FB. It has always been stored under cover before, including last year, which was our first year of ownership. But as you say, given the indoor options which are both costly and frankly far enough away that I wouldn't be able to keep an eye on things like mice etc. - we are thinking we will try a year outside on our property.
All the posts seem the same: keep it inside/under cover if you can, but it can survive if you can't. So with that in mind, if you discover a good indoor option in Northern VT - please share!