2006 Ford Expedition and 3124KB

We are total newbies at this with lots of questions.....
We just purchased a new 3124KB. We also bought a 2006 Eddie Bauer Ford Expedition with the heavy duty towing package as our TV.

We have 6 people in our family ~ total weight 900 lbs. The tongue weight of the 3124 unloaded is 448lbs, we just discovered the max gross cargo and passenger weight for the TV is 1474lbs. With as many people as we have can we use the Expedition as our TV? Are we too close to the max?? What about when the younger kids get bigger or Grams comes along? We had planned to go camping with this setup in CO, Dakotas, etc-- mountain areas.

Also do we need a WD hitch? The TM dealer said no, but now we are questioning that. How would a WD hitch effect the load on our TV, especially with as many people as we have and the weight in our tow vehicle? Will a WD hitch further reduce how many lbs (people, cargo)we can have in the vehicle?

We are really to the point of panicking and feeling that we have just thrown away a lot of money on a setup that we cannot use. With 6 people the choice for tow vehicles was limited and the Expedition seemed to be the best out there for us, now it looks like even it is not enough for all of us and the trailor we needed to sleep the gang.

Help!!!!!!! Are we overreacting??? Are we doomed???