Ruth and I have never required air conditioning on the road. We have lived in buses, box trucks, and motorhomes. Going down the road we stay pretty comfortable. We tend to stick to the drier climates in the summer time. With the choice between daily head bumps and the off chance we might go to Orlando in August, I'll go with head room every time.
Not to say we never use air conditioning. In the summer her in Luna County New Mexico, we run a little 6000 but window unit, facing front from the rear. Our 8 327watt solar panels power that, and keep the batteries topped for evening.
Of course we removed all but four of the windows and insulated with 2" foam board on the sides. The solar panels shade 50% of the roof that helps a lot. Being a pusher helps isolate us from engine heat going down the road as well. For us this isn't a hobby. It's our way of life so we make our choices based on what experience has taught us.
I spose if no one is interested in the evaporator I can save them for a solar heat exchanger project I have in my dream storage.