When I look back at your original post, I see you were thinking about electric as well. Lots of PC sailors use trolling motors, and mount the battery forward for trim, and I have helped a fellow PC sailor set up a Torqeedo 1003 for use here on Narraganset Bay. But, for the exposure of Cape Cod Bay, the currents associated with a tidal range of 10', and the potential need for some serious range if a wind shift catches you off guard, I think you'll be happier with fuel.
Until he got a slip in Sesuit, my friend would trailer up to Truro on days with a north wind. I'm jealous of the beaches at both sites!