1971 Airconditioning Installation
The normal route for the electric wiring is near center of the roof. I wouldn't, however, automatically assume that the air conditioner will replace one of the existing vents - - at least if you are planning a "factory-style" installation. At least in my '64 Overlander and '78 Argosy Minuet, the air conditioner was "cut" into the roof based upon measurements supplied by Airstream at a location other than the standard vent locations. The measurement is usually based upon a measurement from the front bow rearward and varies by year and model. My Airstream dealer handled the installation on the Overlander, and will also install one on the Argosy Minuet shortly so the information must still be available to dealers through Airstream.
In fact, if your '71 is like my '78 Argsoy, you should be able to see an outlet in the ceiling indicating where the air conditioning wiring is found - - I don't know, however, when Airstream/Argosy began this practice.
Good luck with your project.
Kevin D. Allen
WBCCI (Lifetime Member)/VAC/Free Wheelers #6359
1964 Overlander International/1999 GMC K2500 Suburban (7400 VORTEC/4.11 Differentials)
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado Convertible (8.2 Liter V8/2.70 Final Drive)