No matter what process you use, you'll be repeating the process every 2 to 3yrs..

It's black iron pipe.

Over the long run,you will shorten the life of the pipe by sanding it. If you want to "do it right",use special wrap that is desighned to wrap 10" below ground up to 6" above ground. You should see it on meter supply line. Frankly,I envy you if this is the highest priorty item around your house.

That's right. No galvanizing at all but the rust is trivial.

If that were mine I'd use nothing at all other than some solvent to clean the grease off the pipe, go buy a can of Krylon Industrial spray paint (maybe six or seven dollars) in glossy medium gray, and put a half dozen thick coats on every bit of pipe I could see. No primer, no sanding, covers pipe dope, lasts forever, causes no problems.

At my house I even repainted the sun blasted meter and supply pipes, but they were grody.

Thanks for the feedback y'all! I cracked up at klem's comment about the priority level of this. I have larger and more important projects going on, but this is part of my larger kitchen remodel and starting to creep up on the priority list now that fall is approaching.