New England Fall Trip - Columbus Day weekend

As far as Vermont, it will be full of families whose children have time off from school.
Perhaps go far north in VT, to Lyndon or any of the border towns such as Averill to perhaps have fewer crowds.

There are many online articles that will give you valuable information. Here is one that I came across:

https://travelerbibles.com/best-time-to-visit-new-england-for-fall-colors-2025/

You might write to Boston Visitor Information. I would expect that there is. a New England Visitor Information.

There is Yankee Magazine and they would be a good source.

By Columbus Day, the leaves might have done their thing and be on the ground. But foliage is going to be monitored and every day, there will be notifications and announcements about the leaves changing and what percentage are we now at.

Would you consider a cruise? Norwegian and other cruise lines offer cruises from either NYC or Boston to Quebec, sometimes round trip and sometimes one way. It is done during leaf peeping and I believe you get lots and lots of maybe uncrowded viewing. I think some of the cruise is sailing inland. Maybe all of it is along the coast.

It is supposed to be a really beautiful cruise.

Added: https://jeff-foliage.com/archives/forecasts-reports/

I also recommend adding Maine into your trip. It's absolutely stunning, especially the coast. I'd add in a dedicated trip to the LL Bean store.

I've been researching a fall trip there and this travel blog has a lot of good info. https://heleneinbetween.com/2024/07/the-perfect-new-england-fall-road-trip-itinerary-for-leaf-peeping.html

Good luck!