btw, ran this a while ago. Mostly went well, but we had quite a lot of hiccups trying to navigate (literally) the area not pictured in the tower. What happens if you manage to break through the stairs and try to climb up (down) to escape. Specifically the geometry and terrain were very very hard to figure out something plausible for. Goblins got away with the ruby, a ton of valuable picked delicacies, and the need to rebuy or repair nearly all of their gear.
Viewing post in Goblinville Adventure Conversions
I can see that! I've come to rely on grim favor rolls a lot when in uncharted territories. Something for terrain might be:
6: Easy to traverse
4-5: Uncertain / there's an obstacle or hazard
1-3: Critical hazard or imminent danger
Once I know how generous I'm being, I can usually decide what's plausible.
> usually decide what's plausible
The issue was that every time we thought we had a decent idea of the physical constraints, without handwaving the entire thing as ludicrous amounts of magic architecture (to our sensibilities), someone eventually noticed that it didn't work out. Not a subtle problem, more like "uh actually if you built a 3d model of what we just described there wouldn't end up being any path between the two floors".
Okay most were a bit more subtle than that one. But that one did happen.