I was at the Land Between the Lakes Rally
this past October and one gentleman from Clarksville TN has this setup in his Uhaul
Mounted on the tongue is the aluminum box with the A/C unit inside the box. Th box is vented as shown and he modified the cold air discharge and return air on the unit in the box to have these the cold air discharge and return air to be ducted through the 2 hose outlets shown at the side of the box and into the front of the trailer. One hose is for the cold A/C air discharge and one is the return air. Inside the trailer he ran the cold A/C hose discharge under the cabinetry to the rear of the trailer near the sleeping area. Same with the air return hose.
When using the A/C he hooks 2 hoses between the aluminum box that contains the A/C unit and the trailer thereby sending the cold discharge air into the trailer and returning the air from inside the trailer.
In this situation this is NO split unit. Just a window A/C unit modified to direct the cold air discharge AND the return air to the window unit mounted in the aluminum box. When in use he leaves the box open to provide any additional air the unit might need to run properly. He powers the A/C unit with a generator.
Neat, compact, inexpensive and it locates the A/C unit and the noise outside of the trailer.
A unique and different solution to your A/C needs.