Yesterday I finally managed to fix the rooms properly, with mazes around the room, all having doors leading in to the rooms. There are still some flaws to be worked out, where in rare cases a room could have no doors, but the solution is already in my head, ready to be implemented. The next step now will be to implement some simple corridors between the rooms instead of mazes, then go back and fix the rooms. It is only in really rare cases that rooms do not get doors, so this should be unproblematic.
This is how it currently looks, with our fantastic skeleton standing in the middle, wondering about the meaning of life.