It took me a little longer than expected to finish my game, due partly to a cancelled session, and partly to the exiles believing a wandering soul that the Gate of Exiles (which they found at the start of the second session) was not actually the gate, but all three managed to escape in the end.
I was wondering if anyone would be interested in the method I used to create the Dark, which used a semi-randomised deck of encounters and denizens to create the Dark as we went along. That meant that I, as GM, didn't know where the Gate was any more than the players did, something which I felt really suited the game.
I can go into more detail if anyone is interested, or even try and write up the method as a PDF.