The hitch receiver on a 2003 Ford Explorer is 2" x 2".
Install a receiver on the truck and then purchase a drop hitch of your choice. Receiver will cost you around $125 and the drop hitch around $35 with ball. A receiver type hitch is the only way to go. Towing off the bumper is a bad idea.
Yes, with the proper receiver and hitch.
No, this hitch is no longer being used in North America and would need to be replaced with a square receiver in order to use bike racks and the like.
U-Haul
Yes
Yes, but not a bumper hitch. Install a undercarriage trailer receiver hitch system.
Trailer Hitch Cargo Carriers add storage capacity to your vehicle. It slips into the hitch receiver on the back of your tow vehicle and locked into place with a hitch pin.
A hitch is a pattern where the receiver runs upfield then stops and moves toward QB for the catch
Make sure to check the ball size and hitch size are the same first. Other then that yes, it just means the ball can withstand less weight then the receiver hitch.
U-Haul has a wide range of towing hitches and 3 different classes of measurement. Their store features 10 types of hitch and 13 parts including the receiver. Also they offer a hitch installation service where you can schedule appointment and have a professional fit the hitch for you.
I suggest you purchase a receiver type hitch. They come with complete instructions.