Do you have reservations for the 9/11 memorial, they are required. I would start at the Museum of Natural History area of central park (too big to do the whole thing in one day) for a morning thing, then hit Times Square. the Empire State building may be your biggest problem as the lines there can be atrocious, especially on weekends. If you are touring MSG, there may be tickets or reservations required as well. The 1, 2 and 3 subways will take you to most of your destinations except Grand Central, you can catch that by taking the shuttle train from times Square to Grand Central Terminal, about a 20 minute round trip. There is a one day unlimited ride metro card for the subway which will save you alot of money vs. cabs, although a NYC cab ride is much scarier than any roller coaster, if you are into that kind of thing. The top of rockefeller Center may be an alternative to the Empire state building, you have St Patricks Cathedral, Radio City Music Hall, in that area as well. If you walk south down fifth avenue from the park you can cut through Rockefeller Plaza to get to Times Square. I live an hour away and i have only seen probably %0.01 of what NYC has to offer. good luck!