Much to my surprise, I found a mold growth in my carpet!
You cannot salvage the carpet so I cut it out.
I guess it is time to replace the carpet. I have a leak around the front passenger window and we've had lots of rain this year. I do have the new seals to install. I did check behind the panel and the insulation looks OK.
Fortunately, the wood cleaned up pretty well and is still solid. Now I need to find a source of the orange carpet. My carpet is about 100 shades of orange, rust, copper, and gold.
I am just going to go with the University of Texas burnt orange (Pantone Matching System 159).
I did find a shop that produces carpet sections based on PMS numbers.
Pantone Carpet Ten | Camelback Displays, Inc.
I would guess a 10x20 or 10x30 section would be enough for my 20' Argosy.