Ford's Towing Guide for 2013 Explorer. Even if you have all the equipment for the 5000 pound limit, note that the Explorer has frontal area limits, 40 sq ft for the HD Towing Package, even less than the regular towing package.
Frontal area is an important specification because at highway speeds, most for the load from towing is wind drag, not rolling friction. 40 sq ft is about the frontal area of a pop-up. Full height travel trailers range from about 60 sq ft for egg shell compacts like Scamp or Casita to 80-85 sq ft for larger family trailers.
I'm well aware of this limitation, because it applies also the Ranger, and earlier Explorers that were more truck like, and I have to cope with it choosing what I can tow. For any large enough for a family, for me it has to be collapsible or I need a bigger tow vehicle.
Total weight is the trailer and everything that goes into it when you are moving. For passenger vehicles, that 5000 pounds usually gets reduced by the weight of people and goods you load into the car.