Planning my rust repair

[BHM298]

Alright, it's time for me to start my parts list on what to buy/where to buy it from for my 68 longbed. The cab I have needs a good bit of sheetmetal on the bottom end. Rockers and cab corners at a minimum. I need to get underneath and look to see how bad the floor/cab supports are. That being said, what companies should I look into/shy away from? I have seen rockers and cab corners dirt cheap, but didn't know what was junk and what was worth my time.