I can't get th rear drums off. There are access knockout plugs on the back side of the plate that mounts the wheel cylinders. If I knock out the plug, can stick in a screw driver to adjust the shoes in to allow drum removal?
Which direction do I turn it??

If the brakes are the standard Morraine drum brakes, you should be able to remove the knockouts in the backing plates, then use a brake adjusting spoon or screwdriver to rotate the adjusters. The adjusters should be turned so that the outboard side of the adjuster star wheel rotates upward.

You can get rubber plugs to close the adjustment openings in the backing plates at most parts stores.