tweezer on Family Tree Circles

I am trying to find something on the family of William L.(possibly "Lawrence"), Walker from VA, County unknown. He is my great-grandfather. He married a lady by the name of Sarah F. (MNU). William was born in 1836 or 1837; his father's name is unknown to me, but his mother's given name was Susan S. (MNU), she too was born in VA. They had three children born in VA, Hellen E. Walker, b. 1854, William P. (twin) and Susan A. (twin). Twins were born in 1858.

William Walker and his wife, Sarah, show up on the 1860 census in Knox County, TN, with these three children, and another son, Cornelius Daniel Walker (my grandfather), b. 1861, in TN, William's mother, Susan, is there also but not his father.

They show up in 1870, in Fayette County, TN. (William P. is not listed and he would have only been 12 years of age, he may have died within the 10 year span.) There are also more children by then. John W., George V., Lawrence A., Florence, and Sarah Pocahontas, (all Walker children). They show up again in 1880 in Woodruff County, AR, without William's mother. I'm assuming she died rather than moving out. Then I find them by marriage and death records, in Cross County, AR.

My real search right now is William's father in VA. I can't find the father's given name, his mother's maiden name, what county in VA they resided in, nor where in VA his first three children were born. William's mother was born abt. 1810 because she was listed as 60 in the 1870, TN census. I am assuming she was younger than Mr. Walker, therefore, he may have been born abt. 1800 - 1809.

Any help would be appreciated. I have been trying to locate him now for the past 15 years with no luck. From family stories, he was full cherokee. I have checked all of the Indian rolls to no avail.

Thanks,
Tweezer