@willy cheesesteak's god tier list is below. PS, go visit NMWA (make an appointment first).
Early in the day you can go take a peaceful stroll through
Central Park (I like entering through the 59th St/Columbus Circle entrance) or The Conservatory Garden, followed up with the American Museum of Natural History since it's pretty close (and even though I've went here plenty of times as a kid, this museum will always be awesome)).
In the afternoon, you can check out...