In my experience, carpet has served me well in the Deserts and mountains of California. BUT that is because it is basically dry 95% of the time. The times my carpet has gotten wet I was able to dry it out in a day or so.
I have lived in S.Carolina where it rained quite often. I would never have run carpet in an open-topped rig in that part of the country AND the NASTY clay-mud they have there is also an added "bonus" to have to deal with%).
Here in the DRY section of the country I run carpet then just blow the dust out after a trail run and bingo I have a plush "city car" that insulates and is quieter on the road when the top goes back on for the 5 months it needs to be on!
In CA I would throw some insulation down and carpet...not sure what the weather is like on your end of the swamp!? heh-heh