Dan~
I know someone whom has a place on the pond inside. He has a runabout with an outboard, and goes in and out the causeway quite a bit, for fishing. He tells me there is a long sandbar in front of the breachway, parallel to the beach. He leaves the pond, then exits to the west, then straight out south. Large rocky area somewhere in there. The tides make a big difference as how one would approach the navigation - local knowledge only - current is strong each way. I would not attempt it with my '26 (36" draft IO), and especially without he in the boat. I thought it might be a good place to anchor over night or day trip, but after speaking to this guy, he changed my mind. The pond itself is shallow once in. I would stay away unless with a smaller boat.
Were you thinking about bringing your boat in?
Cheers!