Chris ,, that weight is just for when you are towing it, as far as what is inside it. But after you put down the stablizer jacks, it can handle more.
I personally can't imagine putting 700 lbs of stuff in the 21dk.
I am kinda figuring in my head but this is what I figure:
Bedding: 10 lbs
Towels: 10 lbs
Bathroom accessories, shampoo etc. 10 lbs
Kitchen plates/cookware/silverware etc.. 30 lbs
Food in the pantry (Booze included):-0 50 lbs
Refrigerator , packed with bottled water 50 lbs
Clothing 20 lbs
Outside storage : sewer hose , water hose , levelers, 30 lbs
So around 200 lbs. That is without any water in the tanks. We just carry a small amount in the tank when traveling. Most every place you camp will have water unless you are boondocking.