Prepper Stash: High Tension
A stash in the Holland Valley, starting at the Lincoln Lookout Tower (which you may remember from Willis Huntley's side mission, Patriot Acts. It's a lot less guarded this time.
Read the note on the outside north corner of the tower to begin.
Turn, and take the east-facing zipline down.
Take the next zipline as well, and then cross a clump of platforms that have become disconnected. You'll have to jump, cross a balance beam, then jump again to reach the next line.
That last line will take you inside the silo of the Strickland Farm.
Getting inside completes the mission.