Other meta-information, from the Q&A session: GRRM is at about 1000 pages; he anticipates maybe 300 more. He hasn't decided whether or not Bran will appear in AFfC, but if so will only appear briefly. Jon and Dany will be the two focal characters of AFfC (in the sort of way in which Ned was the focal character of AGoT). He's not averse to writing more stories in the ASoIaF world after he finishes the series (which perhaps may look more like seven books), but won't write direct sequels to the series. Future Dunk and Egg stories will be getting darker. (No detail was given as to when the next D&E story could appear.)
And both GRRM and Parris were wearing the Brotherhood T-shirts. I wish I'd remembered to wear mine.
...
Bran: somebody had asked whether the Starks would appear, and whether they would be a focus. GRRM mentioned Sansa and Arya, and said "of course Catelyn won't appear again" [this was previously known], and said "Jon also, if you consider him a Stark" [this was greeted with a lot of laughter]. He didn't explicitly mention Bran, so somebody asked whether Bran would appear in AFfC. GRRM's response was that Bran is one of the characters in training, and so at most he'll get a chapter or two, but that he hadn't decided yet. (He made a throwaway joke about kung-fu movies at this point.)
So, I think that Bran will play (at most) a minor role in AFfC, but he'll be back in future books. GRRM said explicitly that he doesn't like writing "training" chapters (hence the kung-fu references).