A few differences from the game

Here is what I propose to change around:

Ludd Whitehill, Torrhen Whitehill, and Gryff Whitehill have already died by this point (it does not really matter how or why. Just assume they perished fairly early on in the War of the Five Kings. Ideally, they could have fallen at the Green Fork or the Whispering Wood.). At any rate, since Gwyn is the only Whitehill left (other than her brother Ebbert, who is at the Citadel, and therefore, cannot inherit anything), she has assumed responsibility as the Lady of Highpoint and head of her family.

Furthermore, unlike her father and brothers, Gwyn is genuinely interested in repairing the hostilities between House Whitehill and House Forrester. She is currently in the process of striving towards that objective. As part of their reparations, Lady Elissa has arranged for both Ethan and Ryon to be fostered at Highpoint as Gwyn's wards. She is taking MUCH better care of them than her father did.

Now that Ludd is dead, House Whitehill no longer holds any resentment towards Asher for his fling with Gwyn. As such, Elissa has already sent her brother Malcolm to Essos to retrieve Asher. They may return much sooner than in canon, and they can come back with Beshka (and maybe Amara, too).

At present, Talia is the only one of Lady Forrester's children who was with her at Ironrath at the start of the game and is still there with her mother right now. However, suppose that when you arrive, Mira is there, too. Do not worry too much about why. Maybe Margaery has given her leave to visit her family or something like that.

Better yet, maybe Margaery happens to be visiting the North just for the pleasure of it, and she is a guest of the Glenmores or the Forresters. This could take place sometime before her wedding to Renly. Sure, she never visited the North in canon. She never even had a reason to visit it (other than House Tyrell's connections with House Glenmore), nor did she ever show any interest in visiting it. Still, we ARE taking liberties here.

How does all this sound?

1. Let's go with these changes

2. Consider some other changes instead