GCH61T Bongard Christmas Puzzles....
I started looking at this about five years ago. A year ago, I had what I thought might be a solution (I was sure about some of the numbers, and guessed others), but when I visited the location, it was no good. So I did some more staring at the puzzle, and some thinking about the hint, and some geography, and I came up with another likely-looking solution. But I haven't been in the area for a long time.
Today I was nearby, so I went to check out my new answer. When I got to GZ, I struggled around for a while, and then spotted a rather good-looking place. I shone my torch into it, and there was a big ammo can! But. I couldn't reach it.
Madame La Baton came to my rescue, though, and with her help, I was able to get the box into my hands.
A very satisfying cache to complete.