Since my hose wouldn't fit in the bumper, I got some leftover sewer pipe from a friend (copied his work), bought the necessary fittings & mounted the holder on top of the bumper. Looks very similiar to the E-Z Hose Carrier.
2017 Chevrolet K2500HD
2009 Rockwood 2106 Mini-Lite
Here is my solution. I ordered 2 stainless steel "quick pins" and 2 stainless steel with plastic covered lanyards. I drilled a hole trough the bumper and cover so the pin slides through and the catch ball locks. I drilled a hole high enough not to interfere with the hose coming in and out and used an aluminum pop rivet to hold the lanyard in place. If I loose the plug, the pin still holds the hoses in the bumper. I can't drop and loose the pin as it is hooked to the bumper. The bumper plug still works as designed so if I forget to put the pin in it still works as intended. Total cost from Amazon.com including shipping was $18.02.
4" sewer pipe...project cost less than $25 in parts. IMHO, bumper is a bad place to store the stinky slinky... it's thin wall and rusts like crazy. Not what you want when you have a spare tire / etc clamped to the bumper.