Bruce your info on the clash in Randolph County is on the mark I believe. I hate not knowing where someplace is so I kept looking....
Seems there was a community known as Rolling or Rolling Home in northwest Randolph county at the appropriate time. In fact it was still on the map in 1895. I'm betting that Ingrahms clash occured there. Can see the map on the link below. So likely the graveyard story is accurate and it occured at Rolling in Randolph county as described.
Yeah it is fun and FWIW I think vol II (1863) is better than Vol I (1862) but then again they are both magnificent works in a largely untilled field, thanks for your labor of love.