Another idea might be to get one of those small ice makers. They make quite a bit of ice - 17 pounds a day, they advertise. This would help with stocking the cooler and supplying ice for the drinks for the kids if they drink out of cups. And you can keep inside on countertop if you have room.
Some campgrounds at least say they don't allow outdoor fridges or other appliances, though not sure if they enforce.
Good luck with making ur choice to keep things cool!
Wayne and Kim
2014 Cedar Creek 36CKTS
2011 Ford F250 King Ranch 4x2 Diesel, added springs
Nights camped: 2014 - 32; 2013 - 23