This is the door modification I was thinking of. There are also links to put the AC in the fixed driver-side door window. You replace the glass with plywood.
is there any air conditioner I could put on my van that would possibly work with what I've described? I plan on staying in moderate weather - that's the whole point, so I don't think I'll need overpowered cooling.
I wish I would have researched more AC units before I had SMB install the Dometic 15,000 BTU Penguin II. As I’ve said before, 15,000 is overkill for my Transit. This Coleman model would have been perfect for our needs. Live and learn.