We always park in the west 50s between 10th and 12th avenues, in both commercial vehicles and passenger cars. Never been ticketed, harrassed, or victimized. Alternatively, you could talk to hotels across the river in Jersey City - Candlewood Suites and Doubletree are two examples - and ask what they would charge to park there for X amount of time. It's an easy ride from there via the PATH into midtown Manhattan. If you go at night, splurge for a trip up the Empire State Building. It's breathtaking.