When you pick up the quest "This can only mean one thing" from Finkle Einhorn, you can get in the mole machine and go back and forth between Hyjal and BRC. Meaning you don't have to waste your hearth and would have a fast way back after the instance.
The follow up to this quest if you do decide to turn it in is "To the Chamber of Incineration!" where you kill an ogre for 33g and 69,800 experience and that's the end of the chain.
So the choice is yours really if you don't want that. I wasn't sure where to put this as it's not really an exploit or a good guide. I didn't see it anywhere else and figured it would be helpful for some.