new york post-show

wondering if anyone in nyc knows of a place between the wetlands and grand central station to spend a few hours after the show (my friend and I are waiting for the 5am train back home)
im a wee youngin of 19 (turn 20 three days after the show, so this is more or less my b-day celebration), so bars aren't really an option (though my friend is 21) so any info on all night diners/coffee shops/etc would be appreciated or anything that happens to be open till 4 at least anything to keep us off the streets and out of trouble, or at least off the streets
thanks in advance
----Ev