The reason the Halloween event is so long is because it consists of 14 daily quests. On Beta, they were being released at Midnight UTC. You could finish most of them easily in 15 minutes (if you were properly prepared), but wouldn't get the next one until Midnight UTC the next day.
If you get behind, the additional quests are still released, you just have to complete the previous ones to get to the next one. (I spaced and didn't do the last 2 quests until a couple hours before the final deadline, but I was able to do them back to back.)