Short answer - Charge at Lincoln (down the road from Loon) to and from, and plan to charge to 90% at one of Jay Peak's wall connectors, and you should be fine.
Long answer - I used to do Framingham, MA <-> Hanover, NH year round in my 85. I would stop in Hooksett and take advantage of quick top-off during a bathroom break (battery range > bladder range).
Charge up at Lincoln (down the road from Loon). Loon has 2 80A WC's I used once when the Lincoln SC was out, so that's an emergency backup. The long promised (3 or 4 years now) St Johnsbury SC would be nice to have in this situation, but you should be fine. The Tesla "find us" map shows 14 WC's at Jay Peak. I'd plan to charge up overnight, then move in the morning. If the WC's are full during the day, I'd have a slight preference for charging at night, so people who are day-tripping can use them.
I spent a cold winter weekend in Dalton NH (<10 miles up the border from Littleton), and did a bunch of local driving without any local charging. Charged at Lincoln on the way up, spent an hour at a public J1772 (Littleton Co-op) on the way out of town and had a late lunch/early dinner, then left for Lincoln. That was time the SC out; I spent an hour or so at the Loon WC (I have twin chargers, so 80A capable), which gave me enough to cross over the mountains and head west to 91 so I could charge at West Lebanon.
I my experience, the car's nav system range estimator uses recent consumption numbers for planning arrival battery range, so it should adjust in winter. Although this is an old 2014 MCU1 S, that's on a much older rev of software then your 3, so who knows what the new cars do.
