Doors are both boring and time consuming. I really didn't want to do them, but they are probably the single most important feature in the dungeon, so it had to be done. After fiddling around with a bunch of designs for self opening doors that didn't really work, I stopped letting the perfect be the enemy of the good, and just went with a half measure that violates most of my ideals.
As mentioned before, they are a little too big for scale, but they are easy to work with, and make the dungeon feel more alien and like a much less mundane place. They are also big enough for trolls, small giants, and even young dragons to fit through when pesky adventurers show up for some fun.
The key difficulty was making a door that fit into the 2.5-inch gaps in my terrain. The little blocks to the lower left of each door are meant to extend the walls, but they get rotated when the door opens.
Not a big deal, because the doors in Castle Meatgrinder at the wussy sort of doors you find in modern D&D. They are Moldvayian antagonists that are hard to open and slam shut behind you the instant you turn your back. Hope you brought enough iron spikes.