As has been mentioned by Bartomos: The dust cap and the big nut at the spindle must be removed. The drum is attached to the Hub and it will not move until the wheel bearing can move. The drum is not expensive.
http://www.rockauto.com/catalog/moreinfo.php?pk=3871815&cc=1497871 As you can see under 30.00 for one. With the hub loose and some pry-bars you should be able to get it loose. Pressure from the pry bar, and a good shot with a big hammer should do the trick. Don't worry about cracking that drum, easy to replace and cheap too. Gloves now and aspirin for afterwards. Not a finesse job for sure. With the pry-bars you can lever the drum off even with the adjuster stuck. The last thing holding it all together are the pins through the backing plate. And they are cheap to. One one bad stuck truck, I pulled the bolts that hold the wheel cylinder to the backing plate, The shoes, adjuster, 2 broken pins, and the wheel cylinder came out as a unit. Then all them parts fell out of the drum like they had never been in there in the first place. I put The drum now empty and the hub back on and It moved easy. No brakes but it would roll. let us know how it goes.
