Well, since i dont own the cata bundle yet, i can say for my self, that i do 5 raids in the Northrend area, and i do them with 6 chars, so in theory, it is most logical to have the hearthstone set to dala

And also, in my case, i leveled 5 of the chars with a friend with RAF in Dungeon Finder, so i have to run aaalll the way from The jade forrest, to Valley of the four winds, to Kun-Lai Summit, and finaly to the Vale of eternal blossoms ^^ Basicly, im lazy... XD Although i guess i'll do it if thats the best place for the bot to have its Hearthstone.