Option 2: Pivot
Keep playing, adjusting the game to reflect the shake-up. Skip forward an appropriate amount of time (see previous page). Make any mechanical changes you need. The specifics will vary case by case.
Pivots like this can be hard. They make you rethink the game's core assumptions. You have to update rules and handouts. You're basically designing a new game. But if you and your players are down for it, it can be rewarding and fun as hell.
The PCs have left Stonetop to help allied Hillfolk clans in a war against their rivals. I write up a new steading playbook for the ally's war-camp, skip ahead a few months, and write love letters to establish the new situation. The next few seasons might involve stealth missions, attempts to secure resources, and pitched battles. When the war ends and the PCs head home, I'll write love letters to determine what happened while they were gone.
The PCs have all died trying to stop the release of Y'aaw'kara (Book II). A new ice age is unleashed and the Howling Curse plagues the land. We decide to skip ahead a decade or so and start fresh with all new PCs, and discuss how Stonetop has adapted to the harsh new climate, updating its resources and potential improvements accordingly. I rewrite the Seasons Change move, update the inventory inserts and gear lists, and give everyone a custom insert for tracking the Howling Curse (Book II).
The PCs have been exiled from Stonetop and have taken up lives as wandering adventurers. The steading playbook will no longer be relevant to them; most of the Homefront moves no longer apply, or would be much harder to trigger, so I rewrite some of the questions in the End of Session move, and update Level Up to require "a quiet stretch of downtime," instead of "a quiet stretch at home." All in all, the game will now play out more like a traditional fantasy-adventure RPG.