Prepper's Stash: Man Cave
Find this stash in the Sunrise Threshing area, east of Fall's End.
You may have to clear some hostiles from the area, but the stash note is on some green ammoish crates out front.
Your first goal is to get to the tall silo with the zipline. Start by climbing on the roof of the small shack in the center of the property (and south of the silo).
Walk across the board to the middle silo, then jump to the third.
Take the zip line down to the fenced off area below.
Once there, shoot off the lock to open the door outside.
There's a red truck just outside. Get in, and back up to connect with the trailer in the fenced yard. (it will connect automatically when you get close).
Pull the trailer out, then go back and open the bunker door that was underneath it.
Go through the bunker, then up the ladder at the far (south) end.
This will take you into the garage, completing the location, and unlocking a custom vehicle paintjob.