Just landed back from 5 night NYC getaway and would highly recommend the Cloisters in the a.m. and then the Met in the afternoon. Yes, you won't see all of the Met in an afternoon, but pick a couple of sections that most interest you and hit the highlights.
After a long day, it was pure NYC to sit on the Met steps in the warm Spring late afternoon sun and watch a duo of comical street performers do their acrobatic display for the appreciative crowd. A nice memory I took from that day.