What to do to my s10?

Well if you dont want to spend an arm and leg, then sell it now! Owning a vehicle will cost you, and fixing it up or customizing it will cost you dearly. So any first gen seats will fit for sure, even the SUV seats so you can get buckets. LMC has the door panels, dash pads and carpet but that will be $$$ to change the color. An upholstery shop will be able to as well for even more $$$$. And to paint it right, you are looking at several thousand if you pay someone to do it. Even rattle can crap will be a couple hundred, and it will look worse than chipping clear coat.

1. So do you want a nice truck? Then you are going to spend $$$ to make it that way, but the end result is worth it if you want more than just something to drive.
2. If you just want something to drive? Then leave it alone and keep it in good condition, maintain it and drive. It will be worth more than option 3 but less than option 1, in the end... It will also cost the least.
3. Rattle can it black. go cheap on everything you do and have a worthless truck that is pretty much considered junk, no matter how well it runs.

Your call.

I am an ex auto body painter so I take that part of any vehicle I buy very critically. If you want to change the color of a vehicle then do it all or dont do it. Well that's my motto anyway. By doing it all I mean the firewall, inside the fenders and door jambs, between the cab and bed, you know ALL! To me there is nothing more tacky than opening a door of a black truck and seeing red paint. That tells me the paint job was cheap, even if it was done well on the outside. Changing the color of a vehicle is a big job. I am replacing the cab of my 4wd truck here this summer, and the cab i have is black... my truck is blue... so I have some painting in my near future. If I wanted to change the color of the truck (which I would love to... Bermuda Blue, or a burgundy would be good), now would be the time to do it, but in all honesty I don't have the shop to do it right, so I will likely just cut it in with the factory color and let the body shop finish the outside. To save some money on the paint work, I like to use a high school skills center for the work. I know the instructor (he was my body shop instructor) and I know the work will be good when it's done. I only pay for materials. They painted my CT90 and it turned out awesome! I cant wait to ride it for the first time. The bad thing about using a college or skills center is they are a learning environment and it will take them a long time to make it all good... they are not fast with their work. What @DougE said about the SEM paint and spraying the interior will save you a big chunk of change, but you will still need carpet and upholstery but that does make things a bit cheaper, and teaches you some good skills.

Good luck and don't be afraid to ask stupid questions. You know the only stupid question is one not asked.