This is a nice campground really close (though still driving distance) to Popham Beach - which is one of the best beaches in Maine, in my opinion. As someone who prefers more secluded, rustic camping, the mix of cars and RVs was not my favorite. But, there were really nice shower and laundry facilities which was a nice bonus for being in a more family friendly environment.
Not for the faint of heart, Knight Island is only accessible by private boat, though there are a few unregulated boat taxis that will agree to take the boat-less out there. It doesn't host a ton of amenities other than outdoor toilets, but it doesn't need to because every remote campsite is waterside, with fabulous access to amazing swimming, gorgeous sunsets, and fantastic hikes across the island (although beware: mosquitoes and black flies in the middle of the island can be nasty, sometimes better to take the perimeter route).
I've been coming here since I was a little kid and after a couple years away from my home state am more in love with this spot than ever. I like to stay in the remote spots that are only accessible by boat or hiking trails for a little more privacy, but they're all gorgeous. The pond itself is fantastic for water activities and the loop around the pond is a great walk or moderate hike - takes about 2.5 hours.
Absolutely fabulous camping experience. Stayed in "quiet cove" which is the tent-only location a bit of a ways from the main campground office, but much more natural and secluded. Was also created pretty recently so the bathrooms were clean and lovely, and all the pathways and landscaping felt really well maintained. Didn't try the food, but there is a nice food stand with woodfired pizza and a lobster dinner on certain nights. The trails and ocean views around Wolfe's Neck Park were fantastic - highly recommend for anyone looking to get out of the Freeport consumer scene.