If you do go there I'd encourage you to check out CPB and tell us about it. I bet it's beautiful.

When we were in Edgartown two years ago we were told the currents were stronger than ever because the south barrier beach of Katama had been breached in a winter northeaster. The only anchoring if you want to go to E-town is outside the harbor between CPB and E-town, and that would be very exposed in any wind direction with a "N" in it. I don't remember the mooring price but I think it was around $40/night. The town has free showers just north of the ferry pier (ferry to Chappaquiddick) and dinghy dock.

Harbormaster (aka "harbor kid" because he looked like he was still in high school) advised us in a conversation to lock our dinghy at the town dock. Lots of theft because the Chappaquiddick ferry doesn't run late and drunks who miss the ferry have the nasty habit of stealing dinghies to get back home at night and abandoning them on the beach... and sometimes not properly secured they drift out to sea on the tide.