Harbor Freight (and other stores) has a trailer dolly with a handle on it for moving trailers around. Cost: about $60.
I bought one, and modified it with wingnuts so that I could take it apart easily and carry it in the basement compartment of the motorhome. It worked great moving the car dolly around!
Since I sold the dolly (a mistake, for sure!), I use it to move the ATV trailer around the place.
The tires have no air in them, but the trailer I use it on doesn't have that much tongue weight, so it really doesn't matter.