John,
Here is Garrett's suggestions:
Mike, I noticed that they didn't mention contacting the cemetery caretaker (if one exists) about a possible burial plat map. I'd go that route as well. Also, Arkansas death certificates if he died when certificates were being used.
Hopefully, this might help.
Yeah, Benton/Washington County Arkansas are hard to find info sometimes. Garrett and I made a trip down there in July and spent the day at the counties archives and a few cemeteries. Went to a cemetery located in a farm field north of Siloam Springs and was able to find Anthony Wright's daughter's and her husband's grave there.