If you are coming into Epcot just for an event/ressie in the back of WS, why not park at the Boardwalk resort and take the boat over to the "back" entrance to Epcot in the WS. (it is called the international gateway entrance, i believe.) you could be to the American Adventure pavilion in 5 min from there. (again, depending on crowd volume. don't try to get there in 5 min if it is 10 min before NYE fireworks or Illuminations.)