At the posted coordinates you will find a sign with three words. From those you can get the coordinates N 37 abcd W 122 efgh for the next stage, where
a = (1,2) * 2
b = (3,5)
c = (3,4) + 1
d = (2,3) - 2
e = (2,6) - 5
f = (3,4) + 1
g = (3,7) + (1,1) + (1,4)
h = (1,5).
The notation (w,l) refers to the lth letter of the wth word from the sign, and these letters are mapped to numbers according to A=1, B=2, ..., Z=26.
At the second stage you will find a man made object close to the path. Let
x = number of arrows on east side
y = number of characters on west side.
To get to the final stage you have to subtract [y * x * x * (2,4)]/1000 minutes from the latitude of this stage and subtract [y * y * x + g + (1,7)]/1000 minutes from the longitude of this stage.