Put a moving blanket in the truck, set the compressor upright about 2' from the tailgate. Have a friend help tilt the compressor, using the tailgate as a fulcrum and then slide in as its laying down. This way your only lifting a small amount of the weight.
You will want to drain the oil first of course.
That's how my son and I got my 800# gun safe out of the truck. A heavy duty hand truck, myself, son and friend, the safe went up six steps, through the front door and into the closet. I still make do even when I have access to heavier equipment.
I don't like making a big project out of things. just git'er done !
