Hey Jim,
It sounds like your place used to be quite the attraction with the awesome rock gardens. Way cool! Is there any way you can contact the previous owners of the property and pick their brains a bit or see some pictures of the gardens in all their glory?
We were able to do just that when my boyfriend bought his remote property. The prior owner shared her photo album with us, and even lent me a couple of really old historic pictures she had acquired from past owners that I was able to copy and blow up.