See what the power load really is. I added a 13.5k unit to our previous 5'er several years ago. It only pulled about 13 amps at full load, so I used a simple Marinco 15 amp plug in the outside wall and ran the wire from the vent in the bedroom over and down the wall to the hole cut in the wall for the plug. The vent area was very strong and the weight of the 13.5k unit was not excessive and we never had a problem with it. I recommend the 13.5 unit because you won't need extra heavy power to run it but it will help give your main unit a break on hot days you can cycle it off and let it defrost without getting too warm in the trailer.
The other BIG thing to consider is that many parks only have 30 amp service allowing a 30 amp plug and another 15 amp plug on the post. You will likely be able to get away with a standard load on the 30 amp line running to the trailer and running the 2nd a/c on the other line, but be aware of your voltage (keep a voltmeter plugged in where you can monitor it or put an alarm sensor on a plug). I ran many many days over 90-100 degrees with both a/c's cranking away on 30 amp sites since I was using the second plug separate for the 15 amp plug running the 2nd a/c. It never shut down except the few times the whole area went down due to high surge loads.
So- my .02 is to put in the 13.5k unit and run a 15 amp plug in the wall so you can hook up without a second 30 amp circuit.
Mat
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