I'd imagine in the ceiling, at or near an existing vent or fan that could be removed to install an AC.
Do you see the wires/breaker pre-installed in the breaker panel?
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5โ turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold