I was there in July. Spent most of my time in the Bronx at Yankee Stadium. If you only have a day, I would spend it in Midtown. Taking the train from Newark you'll end up at Penn Station on 32nd Street so you won't be far from Times Square. For me Times square was cool to see initially, then I quickly tired of the crowd. Central Park is a must see, I didn't spend enough time there. Mickey Mantle's restaurant is on Central Park South across the street from Central Park, if your into baseball history and nostalgia. Don't be scared to use the Subway, its easy, inexpensive and quick.
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