Just a quick little multi. Gather some information from posted, do a bit of math, and then proceed to the final.
At the post coordinates you will find two signs on a post.
A = From the top sign the total number of letters in red.
B = From the bottom sign the 2 digit number after C.T.
xxx = 40 + (A x B)
yyy = 138 + (A + B)
Cache can be found at N43 54.xxx and W079 14.yyy