I like Ron Franscell’s book The Crime Buff’s Guide to Outlaw Texas quite a bit. It has been a useful source on many of our photo excursions. However, Franscell gives the GPS coordinates for Michener’s grave as 30.19949, -97.45192. If you plug that into Google Maps, it comes up somewhere near Elgin.
Michener’s grave is actually in Austin Memorial Park Cemetery at 30.3325,-97.753167, at least according to the tag on this photo and Find A Grave.