Strawberry Park in Preston CT is the most kid friendly campground in CT that I know of. I have not camped there but know of other Grandparents that take their Grandkids there because they have a lot to offer the kids. It is also located near the shore and Mystic which has beaches and attraction for little kids. Mystic Aquarium is a must to take kids to.Older kids and adults would enjoy Mystic Seaport.
https://www.strawberrypark.net