The two times that we've cruised out of NYC, we've found a groupon or living social deal for one of the chain garages close to the pier for cheaper than pier parking. We used to live in NYC and had a monthly spot in one of the local garages; they serve their purpose and we've never had an issue with our car. The way to make it manageable for traveling is to first drop off your luggage and family at their pier and then walk or cab it back to the pier. Depending on where you parked, it's a $5 - $10 cab ride. We're planning to do this for our next two cruises out of NYC.