Since the engine is in the back, the hoses for the evaporator would be very long, however since the fresh air ducts are very effective, I suggest evaporative air-conditioning in lieu of refrigerated!
I remember using this system to good effect whilst driving the Gordini across the Hay Plains after Jugiong in 1981.
A wet flannel hung in front of the vent worked a treat. Given a bit of thought you could easily set up a system in the plenum chamber using an electric w/screen washer bottle to dribble water over a miniature evap. air conditioning pad.
Major advantage - no power loss!
Robert