Welcome aboard, Daniel!
I'm with Kent on the Huck brakes - mine work fine. But ... I drive defensively on mostly rural and suburban roads and try to avoid city and interstate driving. I will *not* drive my '49 3804 on the DC Beltway. So I do not have much experience with panic braking with the Hucks. I would prefer to keep it that way
Anyway, the main things to look for on the one-tons (assuming you are looking at a pickup) is rust in the hard-to-replace items like the running boards, and all of the bed pieces (splash/valance panels, too -- the curved part between the bed side and the running board. Rust in the cab and front sheet metal usually starts in the lower cab corners, floorboards and where the front fenders attach to the cab. The less rust you find, the better. Pull up the floor mats and look under the cab at the lower corners. While the do make patch panels to fix rust on these cabs (whole cabs, even), fixing rust takes time and money. The more rust, the more time and money. So the least rust you can start with, the better. The cab, front clip and rear fenders are all the same as the 1/2-tons and 3/4 tons.
If the truck runs, great. If not, well you have a little detective work to do (check out our tech tip on starting a dead engine). Even if it does run, an unrestored truck thats been sitting awhile will probably need to have its engine rebuilt or replaced. Before you replace the engine, though ... make sure the truck isn't titled off the engine number.
Any truck that's been sitting for a few years will not have working brakes, so expect any truck like that to need a complete brake job. 1-ton brakes are hard, but not impossible, to replace. Pulling the drums and inspecting the brake components is somewhat of a chore so it is not usually done as part of the buyer inspection. But you can use it as a price negotiation point ... ?
The interior should should worn and dusty, but not like a rats nest. If the truck interior stinks like rodent urine ... look for another one as the cab floor and interior is probably pretty rusted out.
Hopefully, any truck you find isn't sunk to it's axles in barn mud. If it is, you probably will have to replace all bearings and seals. You might have rear end damage, too.
If the tires hold air, great -- will make transportation easier. But you'll want to be replacing them anyway. The wheels, on the other hand, should not be too rusty. Surface rust is ok, pitted, bubbly rust is not.
I have to go to work now, so I'll leave it to the experts to finish this.
Have fun looking! One tons rock!