I did that on a plow truck.
Pulled the cab and fixed all the rust. Had the entire cab rhino lined professionally done after a complete sand blasting. Looked pretty good but sadly moisture got in some how and the cancer spread like wild fire.
If I had to do it again- I’d only do one side and not the whole thing. I like 2-3 coats of heavy rust oleum on the inside the floors. Color can be close to outer body but because under the rug - nobody sees it.
Takes a few days to dry but works great.
