I would suspect the cable which actuates the parking brakes might be rusted up. Put the rear end up on jackstands and see if the cable goes slack at the front end, but doesn't move into the cable housings when you release the brake lever. If the cable does move into the housings, put the thing in low gear (still on the stands) and let the clutch out to break the shoes loose from the drums -- no more disassembly necessary. But if it is a corroded cable, you'd better be ready to spend a few days squirting PB Blaster or some other strong penetrating oil into the cables from the front.