A few comments on myself.
1. I been camping too long to remember. KOA camps are not always RV friendly. Some parts a much nicer than others. But some rules are just crazy. I try to avoid KOA and all cost.
2. If you every question the rules before you go. Simply call the camp RV owners office. I find 95% of the time they are helpful and very friendly to help. I know some have rules as the one poster stated. I fully understand her/his concerns.
3. I have a 30ft TT w/ slideout and only 2 kids. I can not imagine how it would be adding 3 more people 7X24. I would see if you find a RV park that allow one additional tent on the site, some will allow. I would put 2 of the older kids in a small tent to save the entire family sanity.