I have the 3rd row seats removed and used one of the mounting holes to secure a flange I had a welder fab up for me. I used flexible sheet metal to get just the right bend to follow the contour of the inside of the cruiser and then had him copy it with steel.
Since I took the pictures I’ve added a better shutoff valve on the spout and a uniseal with a threaded nipple for an air vent on the top.