just throwing this out there for conjecture -- what's the possibility that the living cannot hold/defeat the dead at Winterfell and have to beat a hasty retreat to King's Landing where by episode 5/beginning of 6, the remaining living forces use the better fortified King's Landing to defeat the dead and have the final battle for the Iron Throne?
I don't see it as likely but if Jon were to take out Dany, that would be the best place and time to do it --> when the dead are defeated and he doesn't need the Dothraki or Unsullied to fight that battle any longer. Also, whoever is destined to kill Cersei would be in the city to do so.
Here's a related mystery: at least twice, characters have had visions of the throne hall in King's Landing - the hall empty, and snow falling in through a hole in the roof. Dany saw that when she visited the House of the Undying, and Bran saw it when he was in his early three-eyed raven days.
So, what did it mean? Was it just a metaphor, or is something going to punch a hole in the throne hall and empty it out - something like Viseryon?
I always liked that because it can be read at least 2 ways - one is that winter, in the form of the Night King, will take/threaten the Iron Throne, the other is that "snow", in the form of Jon Snow, will. And it could even be both in succession! Don't know how literal the hole in the roof will be but the conflict is coming there I'd say.
I've seen speculation that the coming Battle of Winterfell against the undead will be a rout, which would make sense given the timing. There needs to be a major defeat that causes everything to appear lost before the final salvation.
So it would make sense that the battle would ultimately end up at King's Landing.
I also agree with the speculation I've seen that the Night King threat will be resolved before the final episode, and the final episode will involve a last struggle amongst the survivors as to how power will be disposed moving forward.
My hope is that the show actually ends with NOBODY on the iron throne, and the result of the "game of thrones," at long last, is that the game ends, and the realm moves forward with some different path for how the people will be ruled.
But that might be too heavy a lift given they only have 6 episodes.