At the initial coordinates you will find a wooden post with the numerals 185 down the eastern side. You are looking for phone numbers associated with a sign that is also on the eastern side of the post.
On the first phone number, take the 3 digits which follow 800, add them to the last 3 digits of the north coordinate, subtract 205, and this will give you the final 3 digits of your new north coordinate.
With the second phone number, take the 3 digits which follow 800, subtract them from the last 3 digits of the west coordinate, add 7, and this will give you the final 3 digits of your new west coordinate.
Now get after it! You're burning daylight!!