(Rodney) a smaller compresser yes, but not sure if these are still available today, but they had integrated units, which were aftermarket, which fitted into or near the heater box....and the air came out of the dashboard vents.....(this was in my original Sandman)
You could actually still run the heater onto the windscreen, and have the air con blowing cool air on your face

(Jennie) yes I am soft, but R did a lot of driving out to Ivanhoe (sheep station country near broken Hill) and it can get up to 45degrees out here.....