What is your timing? By mid October a lot of campgrounds are closing up for the season.
Be aware that some state parks in Connecticut have limited hookups, most have no hookups (electric, water, septic).
Mystic KOA is a good campground. You have Mystic Seaport and Mystic Village in the area.
Hammonassette State Park has campsites with limited hookups (electric only, with water available to fill tanks) and some campsites are within a stones throw of the beach. I don't know what is available now or will be available, as the park usually fills up during the summer with reservations.
Seafood - right near Hammonassette is Lenny&Joe's, well known seafood place.
Gillette Castle State Park is neat to visit, and there are a bunch of campgrounds in the area.
