Thats a tough call if you cant get parts, even the simplest repairs will keep you parked at the curb.
I'm not positive, but I believe the ball joints have the a plug in place of the zerk grease fitting. If thats the case you may be able to solve that problem pretty easily, by installing a zerk, and fill her with grease.
And the same goes for the upper control arm. Easy fix for squeaky suspension.
These B trucks are pretty easy to keep running, if you can get the parts.
In your case I'd check it over very well and try to get it as cheap as possible.
Good luck
Bobmo