Before making any plans that require you to be someplace at a certain time and taking the train out of the meadowlands, google

new jersey transit u2

to see what a disaster it was for people taking the trains after the U2 Concerts. They expected 7,000, they got over 20,000 people. Lines were over three hours long to get out of there. They have changed back to running busses and the trains again hopefully that will help.

There is no easy way to get out of the Meadowlands. If you get a car service that knows the place, they can park at one of the lots that lets them get onto the road quickly, but that will require you to get to them, probably a 15 or 20 minute walk to say parking lot 29 or whatever it is. It is not at all unusual though for people who want to park right next to the entrance to the stadium to be in their car for hours after the event just trying to get out of the parking lot.

You may get lucky, but not a bet I'd make.