Not KW, but I would enjoy meeting for all of the above if I didn't live in hot & humid Houston, Texas!

It will come from the hot Humid attic, crawl space, swage, windows, etc... with lots of humidity and your a/c will work harder.

It has no ducting attached to it, and humid air is just pushed into the ceiling.

The information on sizing isn't correct, the worst thing you can do is oversize the units because they won't control humidity and they won't last as long.

Somewhere without earthquakes,  tornadoes, hurricanes, tons of rain or smothering humidity, floods, ice/snow, high property taxes, any state income tax or loose soil slab foundations but reasonable landlord/tenant laws.    

Coastal/humid/rainy climates will cost 3x normal maintenance.

So my recommendation would be to:Respond in writing - text or email - that you are committed to her having a working air conditioner for her trailer - especially in our hot and humid summer. 

If your lease has these terms, then turning off power would be a lease violation, and would potentially justify retaining the security deposit.Yes, pipes could freeze in the winter, but there are also other problems that could occur with no power.Most areas of NC are highly humid, and not having AC and consistent air circulation in the summer could cause issues with humidity buildup inside the house, which could produce mold, rust, peeling paint, and/or wood rot.

Humidity- determine if you need a dehumidifier. 

For those not familiar with the area, summers are hot and humid.