I also love the north end of Central Park, although you'll probably have better luck if you look below 110 St - just take the 2 or 3 train to 110 St or the B or C train to 103 St or 110 St. Before or after the park, you should take a stroll up Lenox Av aka Malcolm X Blvd which I think is the loveliest boulevard in Manhattan. You will find a lot of interesting architecture in Harlem especially on the side streets. Of particular interest are Strivers' Row and Aster Row (130 St between 5 Av and Lexnox Av). When you get hungry, you might head to Amy Ruth's for chicken and waffles.

If you do head to Sunset Park in Brooklyn, the city's third largest Chinatown stretches south along 8 Av (just east of the actual park). Also in that neighborhood, The Green-Wood Cemetery is certainly worth a look.