At the least I would pull the drums to inspect the brakes and the bearings. Meaning, I'd wash out the bearings (using a solvent), dry throughly, inspect, pack and reinstall.
As for the brakes themselves, it's hard to say what to do without seeing the condition. Assuming the shoes have some lining left, I'd probably wash down the parts with some Brakleen, knock the rust off the drums with some emory cloth and make sure they weren't binding up. Then depending on the condition, I'd replace the assemblies at home.