That is a great idea, if the dimensions fit you should be gold. Take pics and document the process, you can share it here with the others. Those latest technology window units are rather efficient.
The best implementation of a replacement AC process I have seen is where a fellow took apart a unit, put the compressor and condenser outside under the van with a fan, and the evaporator and a second fan inside under a sofa! Further, optimized by dripping the condensate on to the coil under the rig. He reported being able to boon dock with less energy needs and less noise. He had all the AC repair tools to be able to drain the refrigerant, and then evacuate and re pressurize the system etc. He used sound proofing techniques when and where needed to isolate vibration and noise.
Best of Luck on your fix and welcome to the forum.
RUSTIC is good.
Kudos to those who make Local, State & Federal Parks & Campgrounds possible and to those picking up the slack by Providing Private Campgrounds.