Take a NJ Transit train to NY Penn Station. Follow the signs to the NYC Subway (1, 2, 3 trains), take an uptown 1,2 or 3 for one stop to 42nd St-Times Square. At that station use the stairs at the front of the platform and make a right at the top and go to the 42nd St Shuttle (S). Take that train (any track) to Grand Central (1 stop), walk down the passageway and take an uptown 4 or 5 (express) or 6 (local) to 86th St. When you exit to the street, cross to the other side of Lexington Av and continue walking along 86th St for 3 (long) blocks to 5th Av (Central Park). At 5th Av make a left and walk to the Museum at 81st St.