Thanks for the input-I'm mostly hearing I should just replace the parts, making it look better could damage already worn parts, and that no one else but me would appreciate the work anyway.
I could sell this car for about $1,500 the miserable way it is, or I could put about $500 worth of parts and some of my ample spare time to bring it up to $2,500-$3,000. The interior looked terrible, but with some refurbishment it looks more like it's four years old and not 21 years old. For the interior, I wanted to take out the disgustingly orange rusty screws and either clean them, or replace them with shiny, attractive new ones. It honestly changes the outlook of the car floors and doors.
The engine looks terrible, and was in poor working condition when I got it. Since I'm taking apart a lot of it to replace a few loose rockers, and replacing the rest of the dry-rotted pipes, I figured I should go the extra step and make it shine. Simply getting the grime and excess oil sludge make it more presentable, so de-rusting the bolts and making it in good working order would be a turn-on to buyers and make it drastically more safe for me to drive for the moment (the fixing part, not the cleaning).
I gave CLR (a calcium, lime, and rust remover) as an example of a solvent that may be used, though I'd look for something more specific to what I'm looking for.
I'm also probably going to car parts and home improvement stores to find as many replacements as possible, before refurbishing the existing bolts and screws.
I got this car for virtually free, but I wondered, if I bought another car for $1,500, fixed it and sold it for $3,000, wouldn't I have to pay something outrageous like a 42% income tax on the profits, totally negating whatever profit I made?
E - I'm doing this one for the experience, so I'll know how to take care of a good car, when that time comes.