My Mom has consistently talked about getting an old RV and renovating it to his standards.
His plan was that when he retired, he would have plenty of time to beginning this project, and first, he would have to find an RV that was of appropriate size and condition to do what he wanted with it.
He found a large RV that needed some work. He spent a few hours a afternoon doing repairs to the RV. When everything was up to his standards, he decided it was time the add the air conditioning unit. He went to the local house improvement store and asked the air conditioning system experts which one would be best for the RV. He ended up purchasing an air conditioning system unit similar to what they use on boats. The air conditioning system was perfect for the size of the RV. He would not use it until they were sleeping in the RV, so it did not need to be anything too costly. He was absolutely pleased with the air conditioning unit he put in the RV. He and my mom were able to travel the country and sleep in the RV comfortably. On one of their trips, the air conditioner stopped working. Because they are able to go someplace in the RV, they just drove north until the weather was cooler. This was a temporary fix to their problem. When they returned home, they were able to have the air conditioner repaired. It was an simple fix and the unit lasted another year before it needed to be fully replaced.