Cache is not at given coordinates, in order to find you must complete the nearby Sculptures of Evergreen Adventure Lab. The bonus cache resides at N39 37.ABC W105 20.DEF. Each completed Adventure Lab stop will reveal a digit which corresponds to a letter in the puzzle. You can confirm your final coordinates with the checker provided. Learn more about Adventure Labs here.
This Adventure Lab can now be done in any order, however please read the hint below for a better experience. Happy Hunting.
PRO TIP: Save the Wulff Rec center stage in AL as your last stop, then go find the bonus!