600EX is 'very old'? What's that make me?

A computer is way more fragile than a bicycle, and generally more of a pain in the ass IMO. Unless you're applying some serious forces, there isn't really any way to break most stuff on a bike (stripped crank threads and bent hub dustcaps aside). Take your time, and nothing's really that complicated.

What's wrong with cartridge BBs? Not exactly C&V, but if you aren't doing a period-correct concours restoration, who cares? If you get stuck for a part, try ebay or this very forum - people are quite helpful about shipping parts out at a reasonable price for someone who needs them (Thanks, East Hill!). Don't throw stuff away, there's always bits and pieces that come in handy. Sometimes it's worth buying a heap just for the parts - we did the same thing at the computer shop, we'd strip all the screws, drive cages, case inserts, and offset/mounting bolts out of it and dump the rest in the trash.