See below for info on public transportation from NYC to Princeton.

Public transportation from NYC to Princeton is EASY:

Check the New Jersey Transit train schedule HERE.
Board NJ Transit’s Northeast Corridor line from Penn Station to Princeton.
The train ride should take 1 hr 20-30 min total.
You will first arrive at Princeton Junction Station, where you will get off and go across a short platform to the “Princeton Dinky” train.
The Dinky will depart soon thereafter and takes about 5 minutes to get to Princeton Station.
Once you walk off the Princeton Station platform, the Lewis Center for the Arts will loom large in front of you. The entrance to the Forum (where the performance begins) will be the all-glass doors right across the street from the station.
If you want to eat/grab drinks before or after the show, there are two restaurants— Dinky Bar (lively bar food) or Roots Ocean Prime (steak house/seafood) right up the street!
EASY! DO IT!