if it is in the air, i would roll frame out from under it, then back the trailer under and set it down.
That is how I see them in the yard @ Thomas Built buses in High Point, NC.why not get a couple of 4X4, and some oil drums? slide the 4X4's between frame and body, and set the ends on oil drums. then you can drive the frame out from under it.
cut the front 5 foot or so off the body leaving the driver station, steps, and front door on the frame. this way you can still drive it around instead of pushing or pulling it.