There's a tremendous difference in the art provided by multiple sellers for most arcade games. You can spend as little as possible and buy cheap inkjet crap from an eBay seller or you can usually buy better quality stuff from some of the main vendors. Many people have chosen the cheap crap only to end up buying the better stuff anyway so I would advise you to buy the good stuff first.
When I need art this is how I start my search:
1) Phoenixarcade.com -- Darin is the man when it comes to providing top notch stuff and good communication
2) ThisOldGame.com -- Rich used to print a lot of stuff for Darin and is known for his quality silkscreen work. However communication and turn around time can vary wildly with this seller (I don't mind, but some do so that's why I'm mentioning it).
3) Arcadeshop.com -- Steven is a cool dude and always ships quick as well. I've been pleased with every package thus far (same with the two sellers above).
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4) Everyone else as they're all a distant fourth compared to the sellers above. Personally I'll always support the guys above if they have the art I need even if someone on ebay or elsewhere has it cheaper. If you want inkjet stuff without spending too much money gameongrafix.com has a pretty good reputation though I'd never buy from them if the sellers above have it.
any suggestions would be greatly appreciated on what needs to be done in order...
I don't think there's a right or wrong way to do it, but I think it makes the most sense to sort the electronics before you restore the cab. That way you won't scratch/damage/etc. your restored cab while you're working on getting the game going.