A U-Haul trailer, as I recall, is too low for an upright piano on a
dolly, so you have to slide it in.  Get two guys, one on each side of
one end of the piano.  Pick up the end and put blocks of wood to hold
it up.  (Actually, one guy can do this if it's already on a dolly).
Back the trailer under the end to clear the casters, then push the
piano inside.  Two normal men should be enough.

Be sure to measure first!  U-Haul might rent an open trailer, too.

Philip Jamison