Just a parking suggestion for ya...
The Port Authority (8th avenue and 41st street) has a parking garage, i think it's 25 dollars for the day (other places will be cheaper) but it's in a handy area transportation wise.. subways are there - and everyone knows where the Port authority is if you get misplaced... plus there's a cool statue of Jackie Gleason out front...
and it's a stones throw to the Lincoln Tunnel for getting out of the city.
you could then walk across 42st street- past bryant park... to patience and fortitude - the lions that guard the nyc public library (that's on 5th)
then down to the empire state building