Slick 60's

My next project will be replacing the floors and cab mounts (thanks to carolina classics). Any suggestions on what to expect? Also I've never done anything like this before. I came into my care a millermatic 180 mig and looking to get some hours on it. I kinda wanted to get an idea of what people's opinions were on what to coat the bottom of the cab with. Should i seam seal the inside and primer it up? Like I said never done anything like this and any help would be appreciated.

id think cut out the old weld in the new and seal it up with sealer and prime. not sure what to put on the bottom, i've seen just paint, and some use the bedliner stuff and other just use POR15 and call it a day