looking for help with the design of a fun project (camper AC)

Thanks for checking this out. I'll try to keep this first post brief.

I'm converting a 1983 Econoline into a part time camper/part time hauler. I want to add air conditioning that will run off 110v AC shore power and ideally inverted AC from a battery bank. (ambitious at best)

The van's cargo space is insulated with an average of R6 closed cell spray foam and will be sealed off from the front cab space to minimize air leakage. The volume of the space is approximately 350 cubic feet.

My understanding is that this application would require only a small fraction of the cooling power of even a small window AC unit and I'm looking for creative DIY solutions and practical advice on size and design.

My best idea is currently a window AC mounted under the frame with custom insulated ducting, controls extended to the interior of the van, and auxiliary fans to compensate for the duct resistance. I would do my best to insulate the unit from vibration and shield it from road spray.

Can anyone think of a more efficient setup or ways to improve the current idea? I'm competent with electrical, electronics, plumbing, welding, fabrication, ect., but don't have much experience with refrigeration or HVAC.

5Kbtu/h window unit aut to handle that fine, and most good inverters should be able to start it as well.

Keep the kiss principle.