Nice location for the hose.
When I was trying to come up with an idea for mounting my rock guard/skirt, I had thought of repositioning the sewer hose (as it ended up, I repositioned the skirt so I could keep the rear bumper for the sewer hose).
It's hard to tell, but do you have to go under the RV to retrieve the hose, or does it stick out to the side far enough you can get to it?
I thought that if I put such a holder on my RV, I would add a hatch to the side of the rig; like one of these:
But I ended up scrapping that idea as I could not find a suitable spot to transition the PVC to the sidewall.
But I didn't have any problem considering using a sawzall on my RV...
I still may come up with something, as I would like to carry a short 5ft hose for pump out duty (or perhaps just replace my hose with 2 5ft'ers), and I wanted to wait until the hydraulic jacks were installed so I would not interfere with potential mounting locations.
But now that is done, I can revisit this idea.