There are Two Journals at The Gate Region of Outriders. Both journals are part of the side quest ‘The Outrider’s Legacy‘.
#1 Sarah Tanner’s Journal: Journal location is at the ‘Horrific Sculpture’, as shown on the map. You can find the journal near a tent. Also, This journal is part of the side quest ‘The Outrider’s Legacy‘, you can take this side quest from Trench Town.
#2 Enclave’s Smuggler Report: You need to get down from the left side of the platform and take an immediate right turn. You can find the journal at the end after crossing the swamp.
Where to find Sarah Tanner in Outriders?
You can find Sarah Tanner’s body next to the tent as shown in the image. Video Link
Press E to investigate the body.