Coords are for the starting point. At this location, get the address and use the number to solve for the final cache location.
You are searching for 28d 39.A north corrds and 081d 14.BCD west cords.
for A: use the address and subtract 7,765 = three digit number
for the digits to make up the west coords, treat each math task as a separate equation until you get to a single digit to replace D, C and B.
For D: (Address x 3.142) / 61.494 = X - 0.6311 = X / 207 = X - 1 = D (a single digit number)
For C: (Address - 115) / 400 = X + 22 = X x 0 = X / 1701 = X x 867.5309 = C ( a single digit)
For B: Address - 800 - 681 - 595 - 759 + 2657 - 7000 + 13 - 95 + 402 - 1254 = B (a signle digit)
you could just try to jetskier it.