Hi MSDT-99517,
Congratulations on the new Mallard and welcome to the Heartland Owners Forum.
If your M33 has 30 amp electric service, it's not set up for a 2nd A/C unit, and you'd find it difficult to run 2 air conditioners at the same time on 30 amps.
Also, on 30 amp trailers the roof likely doesn't have the support framing or wiring.
You might have to look at roll-around floor units that exhaust through the window, with an extension cord running through the window to the 20 amp receptacle on the campground pedestal.