I was very excited to see your request. You may already have the following information, but it is always better to get it twice than not at all!
John Monroe Chisum and Mary Elizabeth George are buried in a little cemetery south and west of Altus, OK in Jackson County.I actually met their granddaughter and she took me to the cemetery.It is so overgrown now, that you would not even know it was there.
I am descended from Delilah George (Mary Elizabeth's sister) who married Elijah Kaufman Chisum (John Monroe's brother).
I have made it a goal to track down all of these Chisums--as you probably know, they are a mess!