Prepper Stash: Overwatch
Find the starting point for this stash in the Taft Lookout Tower, near the eastern edge of Faith's territory.
The stash note is inside the tower, on some boxes in the south-westish corner.
There's also a pallid sturgeon fishing magazine on the counter next to the stove.
Your path is going to take you all the way up Raptor Peak, to the east. The fastest way to clear the lower part is by ATV.
Dismount at the 'DANGER, HIGH CLIFFS" sign.
Follow the trail to the first (but not the last) grapple point. This one's of the swing-across type.
Follow the path up some rope-draped ledges. Note that the nest you pass has a medkit in it.
There's also a lootable backpack at the top of these steps, but the path forward involves creeping under some forboding rock to the east.
Follow that trail all the way to the end for another swing across point. You 'll likely have to choke up a bit on the rope to get the right height.
The nest here has a plunger in it (if you're marking your trail). There's another swing-across to a nest with a catcher's mitt, some oregano, and blasting caps.
Enter the cave north of that nest.
Exit the cave and look up for a climb-up grapple point.
There's another point just above it. When you reach the top, look right (east) for some precarious log bridges.
You may want to take a moment to kill or spook the nearby eagles. You're unlikely to recover the carcass, but it will keep them from attacking while you're mid-beam.
Past the log is one last grapple up.
Up top you'll officially discover Raptor Peak, and also some hapless guns for hire being attacked by giant eagles.
This is a good place to skin some eagles (note that the skins don't have to be in good condition to count for the Challenge requirement, so any companion can get in on the action).
The stash itself is on the north side of the peak, by a campfire.
Enter the camp to complete the location.
In addition to the usual loot, you also unlock the flight crew outfit.