Arya mentioned she didn't think she would be going back to Winterfell.
Both Arya and Jon are acting as the moral champions who have witnessed the death and destruction of King's Landing.
All of Dany's army is in King's Landing. No one can keep up with her if she decides to go on a rampage.
Dany's feelings of betrayal are largely focused on Sansa and Jon.
I expect Jon, Arya and Tyrion to be extremly vocal about the destruction of King's Landing. However, Davos is the one who I think will overstep the mark. I can see an argument going back and forth, with Greyworm informing Dany of Jon's 'reluctance' to fight the Lannisters. Davos and Jon accuse her of being mad, Dany accuses them of treachery.
Dany will make a declaration that Sansa has put these thoughts in his head and that Sansa is attempting to rally the North against her.I could imagine Dany going mad queen on Winterfell.
The only plausible way I can see main characters reuniting is if Dany attacks Winterfell.
I don't think she can kill Jon, but I could see the Unsullied and Dothraki against Jon and the Northerners in King's Landing once Jon loses him temper, whilst Dany flies away.
Which leads to an interesting thought. Could Dany take down Winterfell? She has one dragon, but Sansa has Bran. Could Bran be the one to defeat her, especially if he wargs into Drogon. Assuming that he fights Dany/Drogon, could the dragon's mind/Dany's heritage send him back to the 'burn them all moment' back in the Mad King's day? Could he be killed by Jaime back in the past?
Is there any other plausible way that Drogon could be taken down (please no Bronn with a scorpion, I can see that idiot making some crap joke about a small crossbow for tyrion, but a big crossbow for a dragon).
Sansa would be in the North, with Sam of the Reach, Gendry of Stormlands. I could see her proclaim her uncle as Lord of Riverun again, whilst sending Yohn Royce back in friendship to her cousin in the Vale. All one big happy family. Bronn whinging about his castle and Sansa giving him something in Dorne or Casterly Rock instead (the irony being there is no longer any gold there). If Tyrion does die, then I could see him actually feeling that this would be poetic taking on the Lannister's residence.
Without a baby from Dany, I no longer count on Tyrion surving. I think Sansa is set up to rule, which is kinda weird, as Dany does now appear to have a point about her. If that's the case, then I guess everyone in the South gets killed (Jon takes out Greyworm before tho). Albeit does Arya not confront Dany first and goes directly to Winterfell and then uses her face swapping to eventually get the kill on Dany?
Arya getting to Winterfell, isn't really plausible, but as she is soon riding, then any overnight stays for Dany, whilst she inspects KIng's Landing, feels remorse and then has the argument as outlined above, could be seen to give Arya the time to ride back.
An attack on Winterfell, also shows us how clever Sansa is, byr predicting all of this from Dany and shows she should rule, not Jon.
They could just about fit all this in 1 epsiode. It fits, the reckoning we know will happen, a couple of action sequences that have been set upand a resolution to the saga.
After the Northern army heads home, Dany hosts a feast in the ruins of Kings Landing. It's like the reverse of the Winterfell celebration, with Dany being celebrated and Jon feeling like an outsider. Dany calls for quiet and declares that Jon and Tyrion are traitors. As the Dothraki move towards them, the Dothraki and Unsullied begin to cough and choke. Arya has poisoned them all, Frey-style. As her army dies, Grey Worm pulls off his face and Arya declares that it's Dany who is the traitor. Any last words from the Dragon Queen?
Drogon thunders down into the banquet hall. Dany mounts him quickly while the others are stunned. Dany tells Jon, Arya, Tyrion and Davos that they will pay for this and starts flying to Winterfell to burn it to the ground. The others are helpless to intercede as even ravens wouldn't get there before Drogon.
Bran was been watching the whole thing through his freaky white eyes. He tells Sansa and Brienne what's coming. But he wargs into Drogon and forces Drogon to land peacefully inside Winterfell. Brienne takes Dany into custody. Jon, Tyrion, Arya and Davos arrive and hold a trial for Dany, accused of the slaughter of Kings Landing. She is found guilty. Arya offers to be the executioner, but Jon says that Ned taught him that if you condemn someone to die, you wield the sword yourself. Off with her head.
Dany gets her happy ending as they show the afterlife moment of her reunion with Khal Drogo and their child.
Last scene is a coronation of King Jon and a roundtable of who holds what keep. They get a white raven from Oldtown that spring has arrived.