6 Years for One Chapter in ADWD/Carryover into TWoW (Spoilers Extended)

GRRM has often mentioned how the Meereenese Knot (the order in which certain characters arrived to Meereen) caused him so much trouble in ADWD. It is also often theorized just what the "Meereenese Knot of TWoW" (aka Son of Kong) could be about (ranging from too much going on, to killing off a certain character too early, etc).

While perusing some old SSMs I came across this quote:

Well, I finished a chapter of the DANCE this morning. Which ordinarily would not be occasion for comment, but this was a Bran chapter that I’ve been struggling with for something like six years. Bran has always been the toughest character to write, for a whole bunch of reasons, but this chapter in particular was killing me. – GRRM, notablog, March 15, 2008

I knew that GRRM considered Bran the toughest character to write (due to age, amount of magic, etc.):

Some characters are easier to write and some harder, however. Dany and Bran have always been toughest, maybe because they are heaviest on the magical elements... also, Bran is the youngest of POV kids, and very restricted as well because of his legs. At the other end of the spectrum, the Tyrion chapters often seem to write themselves. The same was true for Ned. -SSM, The Drowned God and More

but 6 years for one chapter (I am assuming Bran III) is a crazy battle.

Bran is the youngest of all the human characters that's why he's the hardest to write and it's also the one most involved with magic and these are both challenges.
When you're writing from the viewpoint of a young child you can't just write what's happened, you have to write what's happening just to make it clear to the reader what's actually happening and but you have to phrase it from the child's eyes what does the child think is happening -SSM, Mysticon 2016

TWoW Bran Subject Matter

Sorry for all of the links but there is so much here that it is pretty hard to contain in one place:

• TWoW is going to be an extremely dark book (Bran's storyline especially)
• Bran/Bloodraven will likely use the many accessible weirwood/heart trees in different locations to interfere/involve themselves in plotlines
• At one point GRRM had Bran/Jon becoming bitter enemies, while that has potentially changed, plenty of potential foreshadowing still exists
• With Bran starting to consistently break the Skinchanger's Code, it will be very interesting to see how Hold the Door happens in the book series as well as how much a certain skinchanger affects Bran's plotline
• Time travel is extremely hard to write in any form. Doing it involving a child must be even harder. If interested: On the recent "Time Travel" Discussion
• We also might start (and this is just me speculating) seeing Euron ramped up as a villain for Bran/Bloodraven

Final Thoughts

unFun Fact: We have received 3 Bran chapters since the Clinton Administration.

And there is no gap anymore. "If a twelve-year old has to conquer the world, then so be it." -SSM, US Signing Tour, Half Moon Bay: 17 Nov 2005

If interested: The Once and Future King Bran I Stark (Thoughts on Bran as the final king in the series)

TLDR: It took GRRM about 6 years to finish a Bran chapter (likely Bran III) With Bran being the hardest character to write and Bran III taking place only ~1/2 of the way into ADWD, I think its logical to assume that:

• Bran's story is behind most of the other characters
• GRRM's struggles with Bran in ADWD likely carry over into TWoW
• The magic/time travel and effect on other storylines from the perspective of a child must be extremely hard to write