[dfwright]

That cab is extremely rough. You'll have to buy almost every patch panel currently made, and beyond that, you're going to need cab cuts for places no patch panel is available, or else you're going to spend a great deal of time fabricating patch panels to fix all that rust. I imagine your budget will not be enough for that work. That's just my take. I applaud you for taking on the challenge, and being a fabricator and welder by trade, you have the skills to do it. I just think you're going to need more than $400 in raw metal, cab cuts, patch panels, and welding supplies.

The pictures I see look like a great candidate for a full floor replacement.

I didn't see any pictures of the top. Is it clean, or do you have similar rust in the top of the cab around the windshield, and gutters?