Mary's elf and her fellowship continued to explore the main entry to level 1, and have almost finished clearing it. I ruled that she started with the map of the main area, and have allowed her to explore from there - she has decided she wanted to clear the entire thing before exploring further. As she moves into other areas, I will only reveal sections as she moves into them, and will add mapping as a layer to our sessions. As is, she has cleared about 80% of the complex, and I expect that next session (assuming she survives against the shadows - I expect that to be a tough challenge) will see the end of exploration of the main area, and then she'll start moving into the sub-levels connected to this.
They encountered and defeated another rust monster (I'm re-branding these as ore eaters for now. We'll see if that name sticks), a minor water elemental (4 HD) and 2 wandering ghouls. She also avoided a fight with a minor earth elemental (but she will probably get back to that) and found (among some monetary treasure) a +1 normal sword that detects magic by touch. All in all, a pretty light session that presented little challenge (although the poor dwarf had a tough night; he was paralyzed by a ghoul and the ore eater ate his chainmail armor - that's two suits he's had eaten by ore eaters!).
I'm close to having a solid draft of this primary crossway (15 keyed encounter areas along with an overview of the vaults, a brief history, and some suggestions about how it all fits together). I'll be releasing a pdf of this (8-10 pages when it's done) in the next day or two, so that you can get a better sense of how this place is put together. I understand that when I say that I'm releasing a 'megadungeon', that can lead to all sorts of possibilities; it's kind of like saying I'm releasing a 'fantasy game' - yeah, thanks. That's real helpful.
So, I figure that an 8-10 page preview of what it will really have inside would be a lot better than a few pages of me telling you what it will be like.
I'm starting with the idea that the dungeon itself, at a minimum, has 200 keyed encounter areas spread over three sprawling levels, with dozens of suggestions for ways to expand from there into other areas. How much bigger it gets beyond that is up to the KS backers... so we'll see.
I'm also working on a surprise or two, but I don't want to say anything until I crunch the numbers (and until I try to make sure I can do it!) so stay tuned...