I came across this tunnel and knew that I had to make a cache out of it.
To find the final, you will need to gather information from this tunnel. The final coordinates are:
N 39 30.ABC
W 104 45.DEF
Checksum for ABCDEF equals 23.
A = Number of Birds of Paradise
B = Number of signs on north wall
C = Last digit of year
D = Number of letters in first word of green sign (look high)
E = Number of nails on "Peace" sign
F = Number of bodies of water
Note the terrain and cache size for the final stage.
Good luck!