Preindustrial Light & Magic Redux [NC] Mystery Cache

In order to find the cache you need:

1. Any GPS device.
2. A strong flashlight.
3. A UV flashlight. UV plays an important role in this cache, so we recommend to use at least this or, better, this.
4. A pencil.
5. A print-out of the treasure map below.

Good luck!

Stage specific hints:
I.: Pbzcner gur znkvzny qvtvg va obgu yvarf naq abgvpr n qvssrerapr.
II.: Fgneg ng "vz Ibyxfzhaq"

Checksums:
II.: ubevmbagny purpxfhz bs qrgrezvarq pbbeqvangrf = guvegl-bar.