Thought I would add to the discussion of vent windows but it may not matter if you don't want vent windows for appearance reasons. The function of vent windows can be improved greatly by using the clip on Brezees on the vent windows. The Breezees direct much of the incomming air downward and cool the legs and feet in hot weather. When driving at speed, adjusting the postions of the vent windows with the side windows rolled down allows good ventilation of the cab and deflects wind outward so it doesn't cause all the turbulence you get without a vent window. When the temperature gets over 100 degrees, I wet a kerchief with a bottle of water and wet down my arms and legs. It is amazing how well the evaporation cools the body. I have driven the desert at 110 degrees and was very comfortable using air circulation and a wet rag. Happy to say the temperature guage for the 235 never goes above 3/4 hot.
