Cache is not a posted coodinates, this is a bonus cache for completing the Evergreen Lake Adventure Lab next door. Each completed Adventure Lab stop will reveal a digit which corresponds to a letter in the puzzle. The bonus cache resides at N 39 37.ABC W 105 19.DEF. Solve the nearby Evergreen Lake Adventure Lab for the final coordinates.
P.S. late May and all through June the Elk are calving new babies around the lake, and have been quite hostile/protective towards people and pets. Please be careful navigating around the lake and keep an eye peeled for the local wildife, Cheers!
What is a Adventure Lab?