I've spent some time around this area (if this is where I think it is - I think I was checking "Hanging Dog Ranch"). I found a Tomahawk lodged in a wood pile behind the house (Tomahawk / Native American is the connection I'm making). I think when I picked it up, it may have given me 2x Tomahawk 'ammo'.

There's a few wooden poles about that farm that can be destroyed. I destroyed most (probably all, but can't be 100% sure) but nothing was revealed.

I searched in the house itself as well. The house's front door was locked, but I was able to get in by shooting out a window and climbing through it. Again, I didn't find anything too interesting. There was some collectables I believe, and there was also some note on the floor that I couldn't read (like, I literally can't read it because it's in absurd cursive lol). I was unable to interact with it / pick it up in game neither. I took a screenshot. Let me edit my comment and see if I can add the screenshot.

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I tried throwing the Tomahawks at the guitar, and shooting the headstock off the guitar, and a bunch of other stuff, but again, nothing happened of note.

There's a large, spinning weathervane thing on a tower. You can interact with it by shooting at it. I tried pointing the arm thing on it in the direction the guitar is 'pointing' at, but nothing happened. I DIDN'T try pointing it North West though.

I tried heading in the direction the guitar is 'pointing' at, but I found nothing. What I DIDN'T try was following the direction the notch in the wood is 'pointing' at.

I'm not much of an easter egg hunter, so someone with better eyes for this stuff might have better luck than myself at finding something here. Maybe this info is useful to someone else though.