I have an anchor point within the concrete floor of the garage, at the back but central to the opening. I used it for my lathe, the bridgeport etc

essentially the method is, chock the trailer. use the come-along (ball and tackle) and a series of ratchet straps to drag off the trailer against the anchor point.

If I had a friend, (or a for that matter, friend with tractor) that would of been a great idea :D