Staff Sergeant Balmoral . was a Staff Sergeant from the 3rd Platoon, Cazador Company, 4th Ranger Battalion.
In the first note he's trying to find a route through the Divide's dangers, like the tunnelers and the radiation and doesn't have much hope. The second note mentions his plans to attack Caesar's Legion by surprise.
Unusual for a Ranger, he is referred to by a specific military rank.