I'm not sure why you seem specifically desirious of this unit, the EER is 10.4, so energy consumption is not particularily good, a 5000 btu frigidaire on Amazon for $139 has an EER of 11.1, the same cooling capacity, and will de humidify at 1.1 pints per hr.
This unit at least on the surface seems to have made the size a little smaller, added some remote technology which could be useful if you were dealing with a remote controlled home system, but that appeared to be the main advantage. The standard window unit would cool as well, dehumidify better, use less energy, and be about one fourth the price.
edit add on; Just saw your picture of the trailer, and unless you are planning some cutting of the sheet metal or totally removing the front window you will have a problem using either option that has been mentioned.
Look at the portable AC unit, specifically those that use 2 hoses for cooling the unit. They will still run on 15 amps or less, and you would be able to vent the hoses from either the sliding window, or the tilt out with a piece of plywood cut to fit the opening when you open the window to use the unit. Price should be around $200.