Regarding international public transportation connections between the Maritimes and the US - aside from Halifax Stanfield International Airport and the single connection to Newark from Greater Moncton International, they are simply non-existent.
It's almost as if the entire frontier between Canada and the US east of Montreal is a black void. We don't seem to matter!
I have mentioned on another thread that I thought VIA or Amtrak should establish a trans-border route from Boston to Halifax via Portland, Bangor, Saint John, Moncton and Truro. Given the lack of other land transportation options, I think this could be viable, especially if marketed appropriately for the tourism market.
The cruise ship industry has discovered the Maritimes, it's high time we established a "land cruise" option as well.....