I pulled out the repair manual today and decided to tackle the Emergency brake. It has to work in order for the truck to pass inspection.
After making the written adjustments, with no change in performance, I decided to open up the rear brakes. Did you know that dirt daubers will nest in brake drums? I have photographic proof to post, someday.
Nothing seemed to be obviously out of place or missing inside of the rear brakes. But I still did not manage to make the emergency brake hold.