Cache is not at the listed coordinates. Only a large body of water resides there. Cache consists of a traditional container in a typical hide location. Trails lead almost to GZ. BYOP. Night caching not allowed.
Once you have solved the final coords parking and trailhead can be found at: N minus 0.013, W minus 0.112
The piano keyboard consists of a series of 7 repeating notes that continues up in scale.
This cache will focus on the octaves. Notes are repeated in a sequence of 7 starting with A and ending with G. Each grouping is an octave. Of course none of this matters for the puzzle solve, but it is always good to know what you don't need to know.
To find the cache solve the puzzle below. You can try running the octaves, but don't expect it to be music to your ears.
CONGRATS TO rlobecker