I love the level 5 quest so far, my one caveat being this:
when i was decoding the cards, I was adventuring in the casino. when they finished, I continued to adventure there, assuming that the door would be unlocked in a non-combat. After a while I started to question this, and only figured out that a new location was available after reading this thread. Not sure how this could be fixed, but it really is frustrating. On the other hand, I hit a crapload of jackpots.
edit: wow. just read the post above in it's entirety, and obviously, Tectonics already said it. The whole 'disliking pop-ups' thing makes sense. Could that adventure not have a 'patrol again' link, but just a 'back to the casino' link? that worked in KoL pretty well. Come to think of it, when you find the door, does the location appear immediately, and just not let you in, or does it only appear after you get the card key?