We spent a week at Cherry Hill Park in May. It was a good base camp for exploring the area, and was a short drive to the Greenbelt Metro Station which has a huge park and ride lot. Metro buses come right into Cherry Hill if you prefer not to drive at all.
Cherry Hill was ok IMO. You certainly would never mistake it for the Fort. It had pools, a recreation hall, mini golf and a store. The sites were adequate for our purposes as a base camp, but I wasn't inclined to spend much time sitting outside. There was a fair amount of road noise from the DC beltway, as the park actually sits adjacent to where the beltway and I-95N join up on the north side of DC. Request a site further from the highway and the noise isn't bad. Our site was comprised of hard packed gravel surrounded by scraggy grass. No landscaping to speak of.
I have some writeups on our experiences in DC in my travel blog linked below. Click on May and scroll down. It is a great place to go with kids. So much to do, and much of it is FREE.