Mike,
I will give another vote for Liberty Landing. The other marina is Chelsea Piers, but that is right on manhatten and I hear it gets kind of bouncy in there. Liberty Landing has a great view of Manhatten and the Statue and Ellis Island.
The trip there is easy but can get hairy, so you have to plan for it. If Ocean conditiions are favorable, go out Fire Island Inlet and run the coast to ambrose, under VZ, into NYC harbor and Liberty Landing comes up just past Statue and before the tip of Manhatten on the west there. Running at say 22 knots, I would say its at least 3 hours from Oakdale.
If the Ocean is not favorable, then run the inside, which is scenic and easy, just watch your buoys. Consider a stop in Island Park Paddy McGees for a meal on the water there. You will come out East Rockaway inlet, one of my favorite inlets. From the inlet its a short run to ambrose and under VZ if the conditions are favorable to run.
For the trip home, its the reverse, but have your waypoints marked for East Rock Inlet, Jones Inlet, and FI Inlet, so you can get a line from ocean to inside if you need it quick. If you want the scenic route go inside. If you want to get there fast, go outside. Personally I prefer inside only becuase I get bored running the ocean with nothing to look at. I like to see the homes, boats, bridges, etc, but then you also need to be on your game navigation wise since you must follow the channel.
The times we have done it we have had 6 - 8 foot breaking waves, we have had pea soup fog, and we have had flat conditions. Fog tends to collect around Ambrose. There are alot of large shipping boats coming thru. So you have to watch for them, they don't stop easily!!!
Not trying to scare you, just want to make sure your aware of all the conditiosn for this run, it is a great trip!!
Enjoy.