Well, I'm going to show you what can be done with a name and year - Rufus b 1876 -- watch for various spellings of surnames.
1880 census Collin Co, TX:
Category: Name;Relationship to head of household; Marital Status; Gender; Race; Age; Birthplace; Occupation; Father's Birthplace; Mother's Birthplace.
John W WELLBORNSelfMMaleW42KYFarmerKYN. C.
M A WELLBORNWifeMFemaleW42MOKeeping HouseKYLA
A B WELLBORNSonSMaleW20KYFarm LaborerKYMO
Georgia WELLBORNDauSFemaleW11KYAt SchoolKYMO
L C WELLBORNBrotherSMaleW32KYFarm LaborerKYMO
1870 census Muhlenberg Co, KY:
Welborn, J. W. 32, b KY - no land shown/personal 100
" Mary Ann, 32, b KY
" Alexander, 11, b KY
" Martha J., 4, b KY
1860 census Muhlenberg Co, KY, page 711:
Welborn, John W., 22, b KY - land 300/personal 300
" Mary A., 23, b MO
" Charles A., b KY
Next door, probably parents of John, husband b KY wife b NC matches info forparents of John on 1880 census:
Welborn, Benj. R., 44, b KY - land 1200/pers 500 - Blksmith
" Martha S., 44, b NC
" Levi B., 20, b KY
" Susan M., 18, b KY
" Lewis C., 15, b KY
" George W., 12, b KY
" Mary E., 7, b KY
" Jessee H., 6, b KY
" Benjamin A., 3, b KY
Go to the Muhlenberg Co, KY GenWeb site, type in Welborn in their search feature, up come 48 items, some will be more recent records, but about #10 is the will of James Welbourne[sic] 1826.He lists among his heirs a son Benjamin and then talks about some of his children receiving their inheritance as they come of age.The Benjamin above would have been born about 1816 and a minor in 1826.Sure looks like a connection there.I didn't check out all the other goodies.Be sure to try various spellings of Welborn/Welburn/Wellborn etc in that search feature, too.
That puts you at the U.S. level, on the left click on KY, click on counties, click on Muhlenberg.
Now, for Thomas Albert Markham, you say he died about 1935, but that doesn't give us any idea of how old he was or where he died.What was his wife's name?Any children?Sometimes they are just little clues, but you may have some and not realize how important they can be.
1930 census Dallas Co, TX shows a Thomas A. Markahm 34 b TX, wife Bernice and a dau, plus a mother-in-law is living with them, too.Is this your Thomas?
As for the Feemster, you only mention your ggrandmother is one, but nothing on her name, dates etc.If Feemster was her maiden name then what was her husband's name?Children were born when and where?We build from the known back to the unknown, so we will worry about SC after we find the information on them in TX.(^_^)