The Last of Us Walkthrough: Bus Depot: 3 Artifacts, 3 Firefly Pendants, 1 Training Guidebook and 2 Comics
Right at the beginning, on the highway, you will come across a large caravan. Inside the caravan there are some supplies including the next artifact, a family picture.
Artifact 2: Note to Wife
First floor of the building, left to the bags, there you will find the letter from Graham to his wife.
Artifact 3: Salt Lake Quarantine Zone Map
Right next to the bus, you come into the next area, there is a white tent where you will find the Map
Firefly Pendant 1: Katerina Perich
Run down the ramp from the highway and once you reach the end, next to the white car at the end of the ramp you will find the Pendant.
Firefly Pendant 2: Nicole Hoo
After you run through the bus depot, you will find a large white tent. To the right there is a small blue tent and right of a green tent. Pendant is hanging from a lamp.
Firefly Pendant 3: Natalie Hoo
After you climb to a new area, you will find bus. The pendant is on the opposite side of the bus.
Training Guidebook 1: Bomb Shrapnel
In the tunnel you will find two bloaters. After the fight you climb into the middle of the area where you will find the training guidebook on top of a truck.
Comic 1: Precipitate
After the scene with giraffes you walk down the stairs into a larger open area. There you will find the comic in front of some toilets.
Comic 2: Catalyst
After you have given the ladder to Ellie, at the end of the air vents you find another comic book.