A good place to get chevy parts used is a railroad salvage joint. They get boxes and doors and stuff but they sell real cheap because the parts are lime green or sunshine orange. My local salvage yard is in Prophetstown, Illinois. Check phone books under salvage, used autos, and railroad. I saw a 97 chevy 1/2 ton with a utility box go for $5500 because it was orange. The guy painted it and you can't tell it was a railroad truck.
Those parts should be a problem. Looks like you have a little work to do. I'd start with your local junkya-, I mean, automotive recycling center and if you don't get satisfaction there, check out http://www.autopartsearch.com and see what they have. I searched for your bed real quick and found one for a little over 500 bucks. Kinda steep. When I rebuilt mine I think I let my old bed go for 50 bucks, 8 foot bed, on an 83 with a little rust and few scratches. Good luck. Oh, and how's she run, and what part of the front axle do you need? A shaft or the whole assembly? That could be expensive also.