When we brought the square over we got a flat trailer from uhaul.. pretty cheap.. was under 50.00
Towed behind Nana and Popas truck (trip planned nicely).
We opted for the trailer over dolly wheels because it had been sitting for a while.. didn't know condition of tires, etc.
Keep in mind you need to get a permit if you want any coverage to the car while being towed (though I'm sure you know that

. )