Far Cry 5 > Prepper Stash Locations and Walkthroughs
Stash Mission Start:
There is a note in a box at Armstrong Residence.
Find the stash:
Climb into the burning house through an open window. Then head left into the next room, past the fire. Here, go left. Jump over a blockage at a doorframe. There is a ramp on the other side. Go up the ramp.
From up here, you can jump down to the left. Around the corner, you can jump up a bookshelf onto a burned platform. There are a couple of more platforms up here. Dont go down. Jump the platforms and then go right on the platform to be able to get to the bunker entrance.
Enter the bunker. The stash is down there, freely accessible with 3 perk magazines.