Point of No Return

Before starting the Story Mission Riding Nomad Again, you’ll get a prompt that advancing the story will lock you out of the northern regions. The northern region is the entire playable area you have unlocked at this point. You can’t even Fast-Travel to any of the Locations at all.

During this Story Mission, Deacon will travel further far south, which will introduce a new playable area with new activities, Locations, and missions. The only time you’ll be able to access the northern regions again is after finishing the main story missions.

That said, it’s recommended to finish all jobs, buy all Upgrades, and Weapons you can afford at this point. You’re not required to do all activities such as killing hordes, finding collectibles, or historical Markers since you can set that aside and do it much later in the game. If you want peace of mind, you can manually create a save file before starting this mission.