He already met with the TV folks and gave them broad guidelines for how it's going to go in the books but the minor storylines/details etc. will be different.
The only major difference will be Osha's character; George liked Natalie Tena's portrayal so much more than his book counterpart that he's attempting to expand her role in future novels.
My main fear this season was the show's writing with no novel for basis. I just want to rant off my thoughts so tl;dr & spoiler warning now:
The frustrating thing about Arya's storyline is that the Faceless Men's are so lackadaisical in following their own stringent religious principles. "You must give up all desires to truly be no one" -- The Waif clearly wants to kill Arya. And Arya already showed that she had no desire to kill the innocent, regardless of whom the Many-Faced God wanted. Jaqen proclaims Arya is "finally No One," after he said there are no third chances and when he must know damn well she wasn't going to come back under his employ. I hope there's a larger motive involved there or else this religion will be the Scientology of Thrones. Still might be.
Also, I understand budgetary restrictions, but a few more Faceless Men extras wandering around in the background of the House of Black & White would've made the whole affair far more believable. Arya not having a weapon on her and getting gutted in the stomach was a misstep. Then proceeding to fall, drag, and run with an opening day-old wound is taking the already edge-of-believability of this show and taking it to a length I can't enjoy. Yes, dragons, resurrection, and ice zombies all live on this show, but people die when they deserve to die. Khal Drogo died from a fucking flesh wound.
Breaking midway through the Meereen siege is fine by me because a least I know the scene will be resolved by the finale or early next year--and not in 5+ years like George did to everyone who reads the books.
Hyping up LSH and Cleganebowl in episode 7 was so palpable that this past episode was a fish slap to the face. I'm not a LSH-enthusiast and haven't been since season 4 ended--that would've been the only prominent time to show her in my mind. Even still, showing members of the BWB turning dark and hanging anyone who is/was friends with the Lannisters (the Hound and supposedly the villagers) was too strong an indicator. Fine, they were just a few bad apples in a still noble group and promptly disposed of. But then outlawing trials by combat and sending Sandor north? The Mountain needs to be slain and he needs to be slain by his brother.
Killing major recurring characters like the Waif and Blackfish offscreen is a waste. That's three episodes that we haven't been emotionally jarred by a death (Hodor). Understandably, Clive Russell didn't want to film a fight scene at his age.
I'd like more Melisandre, Ramsay, Rickon, Sam, & Gilly please. Where is Sam going? If he's going to the Citadel in Oldtown still, cool. If he's going back to the Wall, what the fuck. I also feel like we're not going to see his family again and it seems like a waste of great characters.
Tyrion's been relegated to the Meereen Small Council Jester and it mostly sucks. Who thought I'd miss seeing the polarizing citizens of Meereen?
I'm cool with the Ironborn, especially since it looks like they're going to help Daenerys defeat the Masters, and hopefully add their ships to the Iron Fleet for a successful invasion of Westeros. Crossing my fingers that Tyrion and Theon share a moment of silence for Ros.
Varys is most likely going to Dorne for assistance. The hell have the sand snakes been up to? They don't seem like the types to sit quietly.
I really preferred the look of the previous Night King actor, Richard Brake. He had a strong jawline, the new guy isn't as menacing.
I miss Edd.