Chain to a tree and yank the trailer out from under it. Problem solved. Throw dollys under back wheels start it up if runs and move it around. I may have done that a few times. If no tree available yank off with a car or truck, can put dollys under it on trailer but they don't do well unless an enclosed trailer and a slight slope. If want to be more gentle engine hoist and lift back and slowly pull trailer out while letting back down so doesn't ruin frt fascia(or remove on trailer so don't damage it before hand). If no hoist jack up put plywood under the back if anything hanging down so it'll slide off trailer.
I don't recommend uhaul trailers for this as not flat if you don't have a trailer and decide to go get it.
It's not really that hard to get them off, in a controlled manner is the issue. Sloped driveways suck
