Painting Inside of Travel Trailer Bumper

Thanks for the many ideas and suggestions. The hose is the Thetford Titan, I think 15'. It is a heavy duty hose that I hope will last for several years. My trailer is 7.5' wide, therefore the bumper is that length. With the hose compressed, I takes up almost the full length of the bumper, the down side of this heavy hose. I do have caps for each end of the hose which keeps any stinky water from spilling in the bumper.

I will think thru this some more as to whether to paint the inside of the bumper or make the vinyl fence post holder. Happy Camping!