Our all-adult group went for old times sake last time we stayed at the campground. One thing I noticed was so many small children having THE BEST time. Like...more fun than they have in the parks! They were free to run around, scream, play in the sand/gravel mix, get dirty, roast smores, yell at Chip and Dale, sing along with the songs all in the relative cool of the evening. Nobody was cranky or hot.
I think when I have kids I'm going to save a bunch of money and just take them to the Sing-A-Long instead of buying park tickets!