This bobblehead is fairly easy to get, but it comes with a severe warning: do NOT travel further toward the Fissure Site. Going anywhere near will cause a Scorchbeast to rise up and start fighting you. As long as you stick to the Firebase Major camp, you can find a bobblehead inside, on the wooden crates behind the sleeping bag.
Walk directly east and you’ll find Mac’s Farm which is almost completely destroyed. There’s usually a few Feral Ghouls here so take them out, then crouch as you head into the submerged barn. This is vital; a Mirelurk Queen often spawns in the pit next to the barn. As long as it doesn’t detect you, check around this wooden barrel for a bobblehead.
A few steps to the southwest is the Bootlegger’s Shack, right next to the Creekside Sundew Grove. Once again, there’s usually just some Scorched here. On the ground floor, left of the Armor Workbench, are a pile of crates. Check behind them for a bobblehead on a cardboard box.
As a bonus, if you have the level three picklocking skill, there’s a secret door to the basement found outside. You can grab another bobblehead inside, on the tool board right outside the door to the toilet.
Keep going south-west and you’ll find the Ranger Lookout tower. This is very simple: climb to the very top and a bobblehead can spawn on the metal desk next to the orange radio.
Ranger District Office
Climb down from the tower and go inside the Ranger District Office next door. Inside the north-west office is Ranger Simon’s terminal. The final bobblehead can be found on the filing cabinets right next to it.