Yeah - the hannigan ball coupler is only about 8" from the ground when the trailer is level... (to the bottom of the coupler) - Working a drop-hitch on the truc would be doable, but you may drag in a few places (that 8" is farther behind the axle-center in the truck than on a bike).
Dependig on which trailer, it shouldn't weight more than 200lbs, so loading as a dead-lift won't be too fun (doable with the "right" guys though) - 3-guys would make it more stable; getting a grip at the balance point of the side could be a booger with all the rounded body bits & you won't wanna lift from the wheel arches.
Simple answer would be a set of ATV ramps and just roll the thing into the bed (ass-end front, IMHO), or a good-sized dirt loading bump (ditch to drop the truck wheels into, or a hill that'd let you place the trailer above the tailgate height).
If you can fit a sheet of plywood flat on the floor of this truck - the Hanigan should fit ass-end first... If not, then you'll prolly be stuck loading tongue-first.