The above coordinates are the location of the first stage. To
get to the second stage, you need to use the date you will find at
the first stage location, which is engraved into the building. You
will also need to solve the puzzle below. I suggest you solve the
puzzle below before you set off to find stage one.
To get to the third (final) stage, you will need to use information
found at the second stage and also need to solve the puzzle
below.
The cache is an ammo box filled with swag. I have included one
of my pathtags for the first-to-find prize.