This month I've been working on how The Amaranth Saga will schedule NPC (and player) activities like work, sleep, travel, fighting, and patrol. I'm finally getting clarity on how the simulation will work, how characters' actions are tracked, how they are controlled by the player and AI, etc.
There are a few outstanding design questions, like how the conversation system will work (it has to handle delegating tasks, dispatching messengers, spoken and written communication), but I'm finally returning to mockups. Because the game is so complex, how the player will interact with it (and what they can actually do) requires some thought.
Some time ago, I planned to make a complete mockup of the finished product. It would show how a player might experience Egil's Saga from the perspective of its character Thorolf. Icelandic Sagas (like Egil's) are a major inspiration for The Amaranth Saga. They make good examples of the stories I want the game to generate. By mocking-up Thorolf's experiences, I make sure the simulation can generate them.
However, I've found this latest mockup quite time-consuming. The written descriptions of player experience I've made have been more valuable. I'll probably stick to static (not interactive) mockups for a while. After that, I expect to start making prototype games, and Microsoft PowerPoint mockups won't be needed.