Interlude Ideas (Patreon)

So, I'm going to be trying RoyalRoad's writathon which I've only ever managed to complete once, back when this story was new. It's a lot harder to write fast and coherently with an established story, so if (let's be honest, when) I get stuck, what kind of interludes are you guys most interested in reading? Characters? Locations around Fortress City or United North America? Other? Let me know in the comments.