So, I’ll admit to a bit of skimming (not finding this the most readable adventure, given the four parallel plots, I probably need to pick a villain and read it that way), but I did not see a location given for the vault?
Did I miss it? If I didn’t, where would be a good place for large, forgotten?, Dwarven vault?
It varies by season. In chapter 4, the last encounter in each season is the entrance to the vault.
And did anyone else eye-roll on the key options? I’d prefer some thing that needs to be assembled into a contraption/key that opens the door (and has some connection to Neverember...)
Some of them are silly, but the part I like is that if the players have been interacting with the environment and the NPCs they'll know how to find the keys.
Still, I hear you. I like the idea of hiding the keys in the various lairs. If you buy Unseen Waterdeep it will give you another option for that, too.