Hudson River Cuise
September should present you with some better opportunities for sailing. As I mentioned before, Norrie Point is a nice place to stay (aprox. 11 miles north of Poughkeepsie). If you are not adverse to anchoring-- just north of Cold Spring on the east side of the Hudson is a nice little cove with a view of the Storm King Mountains.
There is also a small marina in Garrison that you might want to consider. Garrison is a neat little village to stroll around in. Cold Spring has a great restaurant called the Hudson House that you might want to try.
A lttle farther north from Cold Spring and on the west side of the Hudson is the Cornwall Yacht Club which will take transients if they have the room--not much else there though. Good Luck!! In response to your question regarding time--if you pushed and motored most of the way, you could probably make it in two days. But you are talking about some long days since it is aproximately 75 miles from the Battery to Saugerties (Catskill). I think you would miss an awful lot that the Hudson has to offer.