Hi core:
there are other ways of getting the safe onto the trailer, such as laying it on its back part way up on the trailer, putting a couple of pipes on the trailer and picking up the lower end with pry bars and wood blocks, and use the pipes once the safe is horizontal and flat to roll it further onto the trailer. Then use pry bars again to lift it off the pipes and let it down onto some more wood blocks in order to offload at the other end. My son calls it, "Getting Egyptian", as in building the pyramids.
You will not like the feeling you get with the tractor being overloaded. It's like it's floating, but a bad float.
simonmeridew