It seems all too predictable, which means what I am about to guess is completely wrong:
Dany goes north to destroy the white walkers, falls in love with Mr Snow, who is really her cousin but her family is okay with that anyway. They then go south, leaving Sansa as queen of the north married to Tyrion who she realises is a good bloke after all. And she kills Littlefinger.
Ice and Fire couple head south, recapture the iron throne with the help of Dorn, but with all these deals the seven kingdoms are pretty much fractured and Dorn, iron islands, and the North are not included under the thrones rule.
Jaime kills Cersei, then marries Brienne, Arya meets up with the Hound who saves her life in some way before dying himself and she marries the bastard blacksmith who we haven't seen for a few seasons.
I think that covers everything.