The neatest package I've seen in an installation of AC was a local that
I've lost track of. He had a small unit installed under the rear bench
seat ( had to do some cutting in order to vent it out the bottom of the
van). It fed cool air into the van via the rear heater opening. Had it
hard wired into the van power supply, so all he had to do was turn it
on.

Of course he had to give up part of the storage space under the seat and
had no rear heat source. Heat is something we, here in So. Florida, dont
worry about.
See you on the road-- Bud Yandell