Well, in case anyone is wondering I have it all straightened out now.
I found a different spot a couple of miles down the road that had an opening and I took it. I called and spoke with them on the phone and the issue of occupancy never even came up. Maybe the very nice lady I spoke with forgot to ask.
I must confess, the thought of just registering at the first spot with six people did cross my mind. Like I mentioned before, I understand that "rules are rules" and I understand that it isn't my park and I don't get to make the rules. I guess in the end that's why I didn't spend any time arguing with them and just found a different spot that was more family friendly.
It is interesting that some have mentioned rental homes and the fair housing laws. I do own a rental property. I have also been discriminated against in a housing situation. About 10 years ago my wife and I (we had three kids then) were trying to rent a house. The landlord told our realtor point blank "We don't want to rent to you because your client has kids". This is a blatant violation of the fair housing law. Rather than rent to us the owner took the property off the market. I spent about 10 minutes being EXTREMELY upset about it. Then I decided that if the landlord really didn't want me in his house that much it was probably better that I didn't enter into a business relationship with him (or her).
I am sure I'll be back on here over the next couple of weeks with more questions as our big trip is approaching (it is the second and third week of July). I'll also get back on here to let everyone know how it goes, and whether or not my wife and I can maintain our sanity with five children in 30 foot long box for eight days.