Body Work, Should I?

[1972RedNeck]

I have a 1972 K20 I bought for $100. The cab corners and rockers are rusted through. The floorboards are rusted through next to the edge. The A pillars appear to fine. The doors are rusted through at the bottom in a few spots.

I have never even tried to do body work at all. I would like to attempt to make a rust free free body that looks fairly decent. I have a good Miller wire welder that can run from .020" to .040" wire. I can make strong welds, but they are not always the prettiest. What size wire is best for body work?

What do I need for tools? I have a cutting torch, sawzall, angle grinder, and a rather large selection of hammers. What other tools do I need?

What is the best order to remove and replace rusted parts? Do I need to brace anything when the cab is chopped apart to prevent tweaking the rest of the cab? Can I do everything with the cab on the truck?

Where is the best place to get replacement sheet metal?

The only part that has me really worried is the doors. What is the best plan of attack to fix them?