Most parts are not too hard to find for an FC, as they interchange with many other Willys vehicles. Brake parts are still being made, and can be purchased at any Jeep Parts house found online. Or, see thefcconnection.com for a list of parts sources. I have always been told to buy new brake cylinders, not rebuilt. I think it's good practice to buy new "wet" brake parts. Of course, re-lined brake shoes are O.K.
You may be able to bleed the brakes to see if they will work, if it has only been sitting two years. Then take the drums off after driving it for a few days to check for leaky wheel cylinders. If the Master Cylinder leaks, you might feel it dripping on the toe of your shoe(LOL.)
Some floor pans are being reproduced, such as around the steering column. It will be tough to find a good radiator. You should have one custom built. See how others have made theirs, some angles back toward the engine for more cooling area. I've messed around with radiators and it's best to build what you want.
You should inspect the entire fuel system. You can test the truck to see how it runs with an auxiliary gas tank, like out of a boat. But don't use the old Jeep gas tank and lines until you clean them out thoroughly, and use a new filter before the fuel pump for protection. You will be money ahead. Most problem occur with old gas. (I just made that mistake on Saturday with an old boat I'm buying. If I would only listen to my own advice and use new gas.....lol. I try too many risky shortcuts that don't pay off.)
Don't forget to bring a fresh battery and see if the lights work.