Hi All - After a few years of van use, I didn't think we needed or wanted a roof vent, so i didn't install one during our last rebuild. I am looking to put in a fan now after our last 10 day trip and the van getting stale with 2 humans and 200 lbs. of dog. I don't want to cut into the finished ceiling now. My thought is to put in a window blank on the driver side rear cargo window and hang a fan vertically. Does anyone know why this wouldn't work? Can the fans take a side load? I did quick online searches but haven't been able to locate any mounting instructions for the common brands that say not to do this...