Photographs of existing tombstones in Harkness Cemetery, located in McCammon, are available online.
Many cemetery records for Idaho are included in LDS Cemetery Records which are a part of the holdings of the Family History Library in Salt Lake City. Harkness Cemetery is included in US Vol. 5 page 161 of that collection.
Information about cemeteries in adjoining areas of Bannock County is available on the Bannock County, Idaho Wiki page.
Wikipedia page for the City of McCammon