Sorry not to have replied much sooner.
I cannot find Miles Wentworth Washington in any census record before 1900. I believe that the Mose Washington in the 1880 census may be Miles's uncle.
Do you have any more information or can you give me some ideas?
Moses (the 18 year old in the census) was with Miles on Moss Grove in the 1899 taxpayers list.
Thank you for your help.