Yes the drums can form a rust surface when sitting in wet weather but that rust could not form if the brake shoes, a none metallic material, were in contact with the drums. What I refered to above is the drum becoming rust covered and that rust causing the brakes to jam at the first application of the brakes. Once that happens that action is enough to remove the rust and thing go back to normal.
It may be time to remove a drum and take a look at the bearings. If you overheated a bearing and then shut down you may have a ceased the bearing.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles