Hm, now that you mention it, I also notice the dragon would hardly fit through the tunnels and doors. But since there's not much else in the scene, maybe resizing him would be easier and faster? It would certainly make the city appear larger, and I've noticed that you don't have anything else in the scene yet suggesting the true scale of either the city or the dragon (if we consider the treasure hoard part of the dragon). So if he was just a little bit smaller, but then you added, say, tiny pickaxes and other things left behind by the dwarves in the tunnels, it would still show the dragon as huge, and the city monumental.
I think the story belongs in the thread that goes with the map. You made the right choice by making that space small. I find a large block of text on any map extremely off-putting. A short summary is way more attractive. When I see an interesting map in the thumbnails collection, I usually click on the thread to find out more anyway. As they say, less is more, although I find it takes a lot of discipline not to break this rule.