Register before you do anything else.
Every winter I watch new owners close on a Killington condo in October, photograph it, list it, and then realize they didn't register with the town before they took bookings. Killington's STR registration runs annually November 1 to October 31. You can't legally accept a guest under 30 nights until the registration is in hand. Apply at killington.munirevs.com on the day you close. If you have an existing unit and you've been lazy about renewal, today is the day. Not Monday.
