Harbor Freight has a very handy little dolly for moving trailers. It consists of two wheels with a trailer ball mounted above them, and a handle for towing it. Just put the ball in the trailer hitch, pull down on the handle, and walk away. It works great for my tow dolly and my little flatbed ATV trailer. I even used it now and then for moving my 18 foot flatbed car hauler (it wasn't easy, but it worked).
I modified my little dolly to make it easy to break down and put in the basement compartment of our motorhome.
It is a great little gadget!