Work Text:
The Maid and the Warrior
What if Arya Stark makes it back to Winterfell with Yoren and Gendry?
We have to start with the basic assumption that the Goldcloaks never catch up to the company on the Kingsroad. So what we have instead is Arya Stark arriving back home before the events of the Sack of Winterfell. Several things will change. One, Robb will succeed in convincing his mother to return home. The safe return of her younger daughter changes Catelyn's priorities. Theon is ordered by Robb to escort his mother back to Winterfell, so there is no sack of the city. Ramsay Snow never arrives because Winterfell is not vulnerable. The North Secedes from Westeros.
Gendry's tale is a bit harder to predict. The main question is would he join the Night's Watch or stay with his friends in Winterfell. Arya probably is able to secure pardons for her friends, and in exchange Catelyn agrees to send other recruits to the Wall instead. Gendry becomes apprentice to Mikken and eventually succeeds him as the master of arms for the castle. Hot Pie becomes head chef of Winterfell within three years and Lommy Greenhands becomes a soldier of the North. Gendry and Arya would not get married, because Arya is promised to a Frey.
Robb and Jeyne still marry causing problems with the Freys. Robb has spurned Walder Frey's granddaughters but now the Red Wedding is impossible. The Freys spend years after the Old Lord's death fighting among themselves while the rest of the seven kingdoms wisely stay out of that battle. Arya never winds up marrying a grandson of Lord Walder. Edmure Tully does not get betrothed to Roslin Frey. Catelyn is not there to negotiate that marriage agreement, and the Lord of Riverrun does not wind up locked in a dungeon in the Twins.
Without the fall of Winterfell, the Lannisters no longer can lay a claim to the North via Sansa. This presents them with a unique problem. They can't just let Sansa go back home, nor can they marry Joffrey off to a traitor's daughter. Sadly, the most likely scenario is that Joffrey orders Sansa killed in a fit of rage and his mother is unable to do anything to stop him, like what happened with Ned Stark's death. What happens after that is a repeat of history where a member of the Kingsguard (The Hound) kills the King and is afterwards put to death. Tommen Baratheon is then crowned King of Westeros and marries Margarey Tyrell.
In Summary, Arya's safe return to Winterfell saves the city from the destruction at the hand of Theon Greyjoy and Ramsay Snow. Gendry, Lommy, and Hot Pie all stay in Winterfell and work for the Starks. Robb and Jeyne still marry, but there is no Red Wedding due to the lack of opportunity for finishing off the Starks. Joffrey goes completely mad and orders Sansa killed, which spurs the Hound into finishing off the second Mad King in less than 20 years. The North becomes an independent kingdom, and Tommen is King of the Six remaining kingdoms. All because the Gold Cloaks failed to find one bastard boy that they were sent to kill.