What a unique property -- recall photo you posted few yrs. ago of the beautiful estate. Your grandchild is going to be thrilled with this historical coin collection someday. I've saved my father's silver dollars but not one of them is of real value except to me. My husband collected silver dollars as a child and I keep telling him to check the dates on them. Seriously doubt he has one of the valuable Nevada gold/silver (both minted/late 1800s gold strike days) but the fond memories of collecting is special.
Ditto BluesBrother's comment. Happy treasure hunting.