This is probably better done in a power boat. The inlets, either Jones Inlet or Fire Island inlet are notorious for shifting shoals and currents. There are also bridges to contend with. I believe the southern most bridges on the Wantagh Parkway and Meadowbrook Parkway are opening bridges, but it is has been a few years since I have been there.
There are many tidal flat and narrow channels in the area. Zach's Bay is pretty shoal at low tide. I've attached a chart of the bay with the theater. The theater was originally used for Broadway Musicals and is designed for that purpose and designed to keep out freeloaders. Although there have no doubt been many changes over the years. Scenery was on barges that were towed into a channel between the audience and the stage.
In 1968 I spent a good part of the summer listening to South Pacific while working at the concession stand.