THE CACHE IS NOT AT THE POSTED COORDINATES.
This Bonus is only for those who have completed the Whimsical Art Adventure Lab.
Once you have collected all the clues, use this formula:
N50 AB.BCA W113 BX.YZB
There are a couple of parking spots on either side of Centre St./#2A. Be careful if crossing the street.
Use the paved path to walk to GZ so there is no need to walk on the side of the road.