one AC might not keep your RV cool in that heat. We had a 31' Winnebago with one AC and it never cooled down below high 80's in Arizona. Not comfortable. We went to Home Depot and purchased rolls of the silver quilted insulation and put it over all the windows and skylights. Helped some. You can expect to get 20-25 degrees cooler than the outside temperature. Another option is to go to places that have AC like shopping, libraries, campground rec rooms during the day and back to the RV at night. Good news is that at night it cooled fine and we slept great.