The thing I recall about playing CNA and other big tablers like it (e.g. Hobbit, Axis & Allies, etc.) was when they were over, the replay in debate about how things turned out, especially the simulations, went on almost as long as the game play!

How did the game parallel the actual events, where it divitated why, and then comparing it to other sessions. If we didn't finish the game, aside from the mundane reasons like a parent needed the table, floor, room, or player, it was usually because we found a bad route in the game. Often from a sploiler in the group (I'm looking at you, Mitch! Haha) who took such an extreme tact that made the game play boring or worse, short! The last thing you want after spending a full day or more setting up a game is to have it end in a few hours.