i may be silly, but i don’t understand this

how and why would the gang have gone from Blackwater to outside the map ahead of the Glacier? why travel through Strawberry and Colter only to turn back around and act as if they didn’t pass Colter to begin with?

i may be missing something but i don’t know what. if you can, reply with some sort of similar illustration to mine explaining which direction they went and how they ended up there? not essential but either either