In 2.10, the password to the 1st and 2nd quests used to be qiao ke li, but it seems the passwords for those quests have since been changed.
Similarly, the password for the 3rd quest used to be austin86, but has since been changed.
As for the password to the 4th quest, I'm not even gonna try to figure that one out either!
To be honest, it would be nice if we had unpassworded version of all four of the official quests.