Hi gregw338,
Welcome to the Heartland Owners Forum.
It's possible, but not easy. If you have a 120V AC residential ceiling fan in the living area, you could install the A/C in that opening and use the power that's already there. You will likely have to balance the circuit breaker panel so you don't draw too much power on the leg that runs 2 A/C units. And even after that, you may need to run the water heater on propane/12V DC to avoid tripping breakers.
As an alternative, you may want to consider a floorstanding portable A/C from Lowes or Home Depot. It's fairly easy to run the exhaust out a window in the rear of the trailer. You'll still have to manage power, but depending on what you buy, perhaps it would be less challenging.