Have you considered mounting the drum like people (at least in the South) used to do fuel oil? An angle iron frame with a cradle is easy enough to build, and then put the drum on top of it (at a slight angle). Have your fuel delivered when the drum gets really low, or when you use the last of it. If delivery isn't an option, and you have to go after it, then you can build the angle iron frame under a crane rail or jib crane or add one to your pickup truck. The other option is to have two drums and use one to transport and then pump the fuel into the other. Make sure the pumps you use are fuel rated so that you don't have a fire issue. The reason for the elevated drum as opposed to pumping it into your tractor, is when you have time to go after a drum full of fuel (maybe not quite full) you can hook up the pump and just leave it to pump. If you pump into your tractor, you have to be there to make sure you don't over fill the tank, standing on the step patiently watching the fuel level. Now I don't mean "leave it unattended", just meaning it won't take as close a watch. Plus pumping that much fuel with a small pump (such as the electric fuel pump on my F350) will take some time, something that would be better served in a time frame planned, not required during a busy day of tractor work.
David from jax