I grew up in central VT and lived in Burlington for my four years of college. Loved it. While I obviously can't speak to the logistics of retiring there, I can say that it was a great place to live at age 18-22 and I wouldn't hesitate to move back if circumstances allowed.
Things I would add to your list:
Pros:
excellent public transportation (
bus system)
great sense of community involvement - not just political involvement but also things like neighborhood clean-up days and potlucks
you get all the pros of living in a (small) city while still being close to lots of wilderness, farmland, and mountains
not to mention Lake Champlain is right there, and there's a fantastic
bike path along the waterfront
Montreal is an easy 2-hour drive away
Cons:
depending on where in Burlington you live, your neighbors could be noisy college students - just do your research first
If you have specific questions, please ask!