+1 to what B1 said.
Or you might as well drive there from NY - cross the border in Houlton or Calais, ME. Driving distance from Montreal will be similar: Montreal-Fredericton is 9 hours, and NYC-Fredericton is ~9:40. F'ton-PEI is another 3 hours or so.
I am all for speeding, but 9:40 NYC to Fredericton is pretty aggressive

. 9 hours Montreal to Fredericton is quite doable.