I am in the process of installing an air conditioner in the cabinet under my stove top. I mounted the AC to a 1/2" piece of plywood on 3/4" risers, shown in picture. This allows me to pull the AC out when needed and slide it back in when in tow. When in tow the ac is held in place by two notched boards not visible in picture. The AC can be taken out if not needed when camping in cold weather.
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I made a small drain pan with hose attached to drain the water out the vent panel. One picture shows the drain pan in place, you can see a small part of the drain hose sticking out of the vent door in one of the pictures.
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I run an extension cord for the AC out the vent door to shore power until I upgrade my trailer power, only have 20 amps. This is my first iteration and keeps my 16' scamp trailer at around 79 degrees when it was 98 degrees outside.
Excuse the picture with mud on the door my muddy dog decided to shake off inside the trailer when I was taking pictures.

One question how are you getting the intake air to the condernser without recirculating the exhaust air into it ??

When the AC is pulled out a certain distance the front of the unit is actually inside the trailer and the exhaust fan is in the cabinet compartment which is vented to the outside.
So, the air intake and fan that blows the cool air out are on the inside of the trailer. The cabinet compartment where the heat exhausts to is isolated from the inside of the trailer. I do not have a picture of the AC pulled out but will post one when I can get to it. I will be out of town for a week.. Hope this makes sense!