I agree, you're well on the way, but there are many remaining points to ponder. Starting out with the floppy drives, those in themselves are worth looking at. I generally look for the "made in" part, China? chuck it, USA, keep to sell, many times even Indonesia or Japan etc, you'll just have to figure your own parameters there. That's true in most all of it. Best rule of thumb, probably is start slow with the scrapping, it's sometimes sad to know you tore down a $200 machine for $5 scrap ; )
Also those board prices, you'll find much better pricing for boards here in the buyers section, and if you find one close enough to drive to, you'll also find power supplies, hard drives, etc to be worth hauling(though they're not worth shipping)
It's just a matter of time till you'll have it figured out and be making waves ; )