Adding a window AC to trailer

I did search but most results were about roof mounted units.

I plan to mount the AC in the rear of the trailer, in the bathroom. There is a clear opening from the bathroom to the rest of my 22' TT. In fact, a previous owner had one mounted there. When I did the restoration, I framed that opening and covered the exterior with one aluminum panel that I can detach and cut for an AC. What I'm not clear about is how far into the trailer I should mount it. Do I build a box with just the back panel of the AC exposed, offering a somewhat smooth surface. I know i would have to allow for air transfer on the sides. Do I mount it flush to the inside wall and have the box of the AC protruding outward? That would probably allow for the most air transfer but is it an issue on the road?

Design ideas like above, assuming a non-critical function, usually work out for themselves in the process. I'm looking for tips and suggestions for those that have gone this route before or folks that can think design process through, allowing for pertinent function. Thanks in advance.

No need for sorry because you didn't search for it. I certainly don't care. I ask questions all the time that I am sure have been answered before. Sometimes I search sometimes I don't. Besides I want the most current advice as possible.:)

I use a window AC on an occasional basis during hot weather. I put it in a window and have a frame that goes around it. I plug it into the pedestal separately so it doesn't draw off the coach breaker box. You want to permanently install yours along the side? A significant projection out of the side could be a hazard while driving and might be a violation. Better check first. I have seen them mounted that way out the back of truck campers. Good luck with your project.

Miles