Far Cry 5 > Prepper Stash Locations and Walkthroughs
Stash Mission Start:
There is a note in front of the Horned Serpent Cave entrance.
Enter Horned Serpent Cave:
There's a grapple spot at the cave entrance. Grapple up to the very top. Then follow the quest marker. You'll see two thugs dropping bodies down. You'll need to go down there...
Follow the climbing ropes down. Past the bodies and human bones. Use the grapple and you're inside the cave. Now for the stash: Don't go into the water. From the first lantern you can look across the water. You'll see a second lantern. That's where you have to go.
Jump over to the little island, to the next, even smaller island. From there to the other side. Now, at the second lantern, more jumping to do. Jump onto the rock in front of the lantern, straight ahead, there is a little tunnel to the third lantern.
From here you can see the forth lantern and a climbing rope. Jump and climb up. There's a grapple up there. Grapple over to the lanterns.
At the lantern I called forth lantern, the northern lantern of those two, jump onto the next rock. On the other side, you can see some climbing rope but it's too far to jump. Use the grapple at top.
Grapple over to the ropes. Here you'll see other climbing ropes and a zipline. Jump over and use the zipline. Here's go up the stairs
Go all the way up, some more thugs to kill, down here and at the end of the path is the stash. To get out, take the stairs up. The gate is open now.