West
It hasn't been warm enough to really test it in the trailer yet. In our case it's purpose isn't to cool a 100 degree rig down in high humidity, but rather start it when it is still cooler and allow it to keep the temperatures down as the day heats up.
Size wise the unit is rated for 150 sq ft and our trailer has 187. Luckily I can even it up by closing off the bunks, bathroom and even the bedroom if it gets hot enough. I spent a year figuring out which window shaker used the least power, after seeing it run I now know I could have gone up to a 6000 BTU energy star model.
The only way I can get ours up to the ceiling where is would be most effective would be to box it and butt it up against the window in the upper bunk. I was going to hang it out one of the emergency exit windows but I worry about the frame handling the weight. Under the bunks is least effective but out of the way, easy to use and will look better.
Last thing is if you are not worried about running it directly off the solar, a none energy star unit is half the price, lighter and doesn't use that much more power than mine. (50w if I remember right)