Lots have put a portable AC through windows
. Some have put AC on the top with some bracing to accommodate the weight
. Others put it under a front seat or in the closet. We put a portable AC through the back wall of our Burro
, attached it to the bumper for support and then disguised it as a cooler. If you search, you will find lots of examples. It does not have to be limited to Uhauls, however, most other campers have belly bands.
Good luck! I would not be without it.