I have not replaced a W-body rocker, Bill. They don't rust out here. Thanks for the encouragement. I can answer your non-vehicle-specific questions off the top of my head but might need pics in some cases. Can you direct me to the replacement rocker you would like to use, so I can see if sectioning is involved?
I have a few picture-heavy build and repair threads on different sites that show lots of patch work and some panel replacement. And the tools / products used. And a couple text threads about primers and basic sanding guidelines. If you would like to peruse them I can link you, or you can start at the beginning and just ask me. I certainly don't mind coaching in public, keeps me honest and makes me think twice about advice before I give it. Fire away!