So a few days later we went to https://www.facebook.com/groups/PHMRocks/ and reported where we found "our" rock and mentioned that we re-hid it in Wisconsin. It was in full view, but amongst a huge pile of other rocks. We were hoping the bright green color would catch someone's attention.
So today I was checking back and, low and behold, someone found our rock in Eagle River, Wisconsin and reported the find.
We wondered who found our rock. An employee of the Wild Eagle Lodge? A guest? So we sent this message. No answer yet.
What fun. Hope we can follow our rock further.