Welcome to the bolt.
Once you get the beast where you're gonna be workin on it you should think about jacking it up and puting it on stands, then remove those wheels. Gonna have to pull em to do your brake work anyway, may as well get it over with now.
Bennefit there is you can look at them, see if any are cracked, clean the up with a wire wheel and paint em up, all pretty cheap things to do. I think it cost me 3 4" wire wheels for my angle grinder, 2 cans of primer, & 4 cans of gloss white to do mine. Another bennefit is being able to have a tire/wheel pro look the rims over to really make sure they are still servicable.
Also, FYI, tubes and tires are gonna run you around $1100.
Brakes, do I feel your pain here. I have an almost completely new system in Tater. The only items I did not replace were the drums, shoes, and rear slaves. With the age of that beast I'm just gonna guess you'll be in the same boat. Get the wheels and drums off and have at it. Brakes are a great place to start because moving can be optional, stopping should always be mandatory!
The big dollar (& hard to get) item will be the HydroVac booster, most of the rest of the parts can be found here & there for a reasonable amount.
Seein as you live out in BFE Cali, go talk to your local Napa parts guys, they tend to have a couple older guys that have been doin this stuff for decades. I got almost everything I needed for my rig there. They have the books that go back that far and if you find the right guy, they can find later year parts that cross over, and sometimes cost less. Many Napa shops also have machine shops that can help with other items you're gonna have to take care of.
Also if there's a truck shop nearby, & even your local tractor shops, try talking to them about some of your heavy items like the rear end, gear boxes, and that winch. My local truck shop and the John Deere guys have been a huge help.
Dont worry too much about your sheet metal till you have the truck operable. You can find another cab, doors, maybe even fenders. Alot of that can wait just fine till you have the other things done. You'll want to have a look at the inside of that engine sometime too, my beast ran OK when I bought it, but it was far from OK. There's not much point if it looks purdy but dont move! Plus they are MUCH easier to work on when the front end is torn down.
But yanno what, we’re all getting WAY ahead of ourselves here. There is NO point what so ever, in doing anything to make this old girl mobile again till you go talk to the Peoples Republic of California DMV and see what it’s gonna cost to license that beast. That in itself may cost you more than any other single item, may as well find out now.
Good luck with it, have fun, and dont hesitate to ask for help from these guys on here. They saved my hiney a time or twenty.