I realized that I completely forgot to post this...
(Picture 1)
The black cab I plan on using (which I posted earlier), someone already put in new outer cab corners and steps on it, though they need a little touching up with the welder. The cab does have some rust on it, but its nothing major, until I started looking over the back of it...
Somebody had welded a plate over a rust spot and then caked bondo over that along with another rust spot next to the plate. I honestly almost didn't notice it at first except for a little rough spot where the rust was eating through the bondo.
(Picture 2)
So I proceeded to hack it out. What made it a bit difficult was this happened to be right where the rear cab mounting bracket is, which also had some rust. Well I got that bracket out in one piece and welded and fixed it up to reuse it.
(Picture 3)
Then I cut out the same piece from the old cab to fill in the spot. First time drilling spot welds went so-so, considering I ended up drilling right through the piece...
(Picture 4)
Weld it up!
(Picture 5)
And hit it with some spray can primer!
Not bad for my first attempt at major rust repair!

This cab will need some floor work, but I'll mess with that later...