(The following is copied from the State of Vermont Secretary of State website, Absentee Voting FAQs and appears to passively suggest it is OK for a non-resident of the state to vote in Vermont.)
Absentee Voting FAQs
Is there a specific provision in Vermont law that allows U.S. citizens who never lived in the U.S. to vote in Vermont if one of their U.S. parents last resided in the state?
No, nor is there any provision that specifically prohibits this.
https://sos.vermont.gov/elections/voters/voter-faqs/absentee-voting-faqs/#index