Cache is NOT at the posted coords.
At the posted coords, you will find a sign. You will be using information from this sign to figure the coords for the final. Be sure to bring tweezers and an ink stick!
"The Tiller family donated the building to the Society in YYYY. After years of effort, the Society opened the restored Mill in ZZZZ as a museum"
YYYY - 1089 = AAA
ZZZZ - 1098 = BBB
Final can be found at:
N39 47.AAA
W105 04.BBB
FTF: Animjason, BearAdair, and Grizzlycacher