This is a simple field puzzle.
When you arrive at GZ, you will find a bench with a plaque for Ray Friesen. Use the dates to find the final cache close by.
Take the 3rd digit of the year of death. This is the last digit of the north coordinate. The rest of the coordinates match the cache coordinates.
Take the 3rd digit of the year of birth. This is the last digit of the west coordinate. The rest of the coordinates match the cache coordinates.
Sit a spell and enjoy the view of the lake and the north valley.