Re: A funny thing happened on the way to the Dungeon...
Jkeown,
You're a lucky man, or at least a lucky GM. Having player's that engage their brains before picking up the dice is rare.
I don't know if it's because most players come to the table with the expectation of combat, or because GM's tend to train their players to attack and kill whatever end up in front of them because "This is obviously what the GM has planned, so we better get through it" or both.
In any case, I'd say props to your girlfriend, and the rest of the group, for the intelligence to realize that certain things needed to get accomplished and then doing it without unnecessary bloodshed - especially on the part of the party.
I'd also give you props for allowing the players to take their preferred course of actions. You must be creating a reasonable level of versimilitude for the players to identify dangers in advance of bloodletting for them to have taken such a wise course of action.
Excellent job all around!