Take the axle out, remove the retainer plate that holds the brake drum and hub on, remove the bearing, hit the outer edge of the wheel with a big hammer and try to get it rocking a little from side to side. That should start to get it loose. If the parking brake cable that goes in the back of the wheel is stuck and is pulling the brake shoes, cut it off so it releases the shoes. There is also a big hole in the brake drum to access the brake shoe adjusters but you would have to get the drum to rotate some to get the hole lined up to spin the adjusters loose.