I doubt that little engine diesel or not is very heavy, most of tractors weight is on the truck and that is why it is sitting like it is.
The pic somehow got deleted but I have trailered tractor engines half as big as your tractor without that much squat...
Yeah, just back it up so the trailer axles are doing the heavy lifting. There's really not much to a Ranger. The rear axle is only rated to 2,750#. Each of those trailer axles are 3,500# capacity--yet you skootch the tractor to the front. Use the trailer to carry the weight and the truck to pull it. You only need enough tongue weight to control it.