I have been following the Plattsburgh situation since they closed the base in 1995 and am anxious to see this project succeed... I have a stong hunch that it will; while it will take some traffic from the Montreal Area Airports it would never put any of the airports there out of business... I suspect the situation will be more of a reliever for Montreal and it will take some bite into BTV's traffic as a susbstantial amount of their traverlers come from the NY side of the lake...
In terms of not having a suitable access road, that is nonsense, the exit for the airport is off of the Adirondack Northway and will be a short 1.5 Mile drive on a main road to the entrance of the airport... I really do not see it being any more convenient than that...
Anyway, I am hopeful that someone will announce service to and from this aiport on or before the day it officially opens for business...