I was able to find a short reference to Charles in the Fairplay Flume newspaper dated March 15, 1882, pg 3 column 2 - courtesy of the Colorado Historic Newspapers Archive at www.coloradohistoricnewspapers.org
"Charles Clarkson, a ranchman who has lived near Ed Smith's place, below Rocky Post Office, died on the 8th, at the age of forty-nine. The neighbors showed their respect for the deceased by interring the remains with suitable ceremonies."
I was also able to find reference to his burial at Lake George Cemetery, resource was Park County Archives - Cemetery Records at http://www.parkcoarchives.org
He is listed as Charlie Clarkson - interred in Lake George Cemetery - Grave #49
No new info, but at least confirms what you already knew..