I think the NE market does not fit with Vail's current approach East of the Rockies. Buy a place in NC, WV, or western PA or NY makes or sense with their approach.
But if you are looking at the Boston/NYC metro market there might be 2-3 mountains I could see being acquired.
Key difference in the northeast is that many of these places will be larger and much better developed than the midwestern locations.
Once you narrow things down to the stand alone mountains that could be up for grabs I can suggest three clear options:
#1 Waterville Valley -- It is widely rumored that the resort is on the market for a desired buyer. They have a lot of expansion plans in the works, and some of that stuff Vail could put together in one summer. It has been seeing fewer and fewer visitors, but it is in the I-93 corridor for Boston folks.
#2 Magic Mtn in VT -- They would be a cheap acquisition for Vail, but it would require a lot of investing in snowmaking and lift infrastructure. The downside is the reputation for being an expert mountain.
#3 Bromley -- I have not heard a single rumor about the place. However, it is not owned by a regional player (Peak, Boyne, Intrawest, Powdr, Muellers). It is located somewhat across the valley from Magic, and is family/beginner/intermediate friendly. Pick up Bromley and Magic in a packaged deal and you could have a nice little complex in Southern VT.
Until a conglomerate like Peaks blows up the NE market seems generally stable at the moment.