I bought this waste hose holder from Amazon. I had it mounted on the bumper of our FourWinds. I was pleasantly surprised to have it fit perfectly in the front storage pass thru on the Axis. I thought about screwing it into the side panel but because I will want to take it out to clean and sanitize it, I added a strip of velcro to each end.
PS yeah!! I learned how to put a picture in a post.
I have made a similar setup. But I took a 6" fence post, because that allows me to get everything in, including the elbows. I use this only for the pipe that I use when I drain the black tank. If I drain the grey tank only, I use a different pipe that is stored in the storage holder that was installed in my motorhome. This is a 4" pipe accessible from the outside through a separate hatch and entirely independent from any basement cabinets.