1.  Jordan R. Dodd, ed.  1993.  Kentucky Marriages:  Early to 1850.  Liahona Research, Orem, UT (Broderbund CD-229):

Gaines, Thomas B.

Corbin, Mary Ann

14 Jun 1845

Warren Co.

2.  1850 Census Every-Name-Index/Images (online at Ancestry.com, Image #91 of 129):  District No.1, Warren Co., KY, Roll M432_220, p. 45A, 618/618, enumerated 20 Sep 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):¤•

Thomas B Gaines	39	M		Carpenter		Va
Mary A     "	34	F				"
Joseph R   "	19	M		Carpenter		Ky

Joseph appears to be Thomas's brother, but he could be Thomas's son by a prior wife.  Listed next to William T. & Mary C. (PERKINS) FANT and sixteen households from Mary's probable brother, James CORBIN.

3.  1860 Census Every-Name-Index/Images (online at Ancestry.com, Image #8 of 135):  Bowling Green P.O., District No. 2, Warren Co., KY, Roll M653_398, p. 576, PN 8, 51/51, enumerated 4 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):¤•

Thomas Gains	49	M		Carpenter		250	Virginia
Mary     "	44	F					"
James    "	9	M					"
Sarah    "	6	F					Kentucky
William  "	1	M					"

It's very unlikely James was born in VA.

4.  1870 Census Every-Name-Index/Images (online at Ancestry.com):  can't find.

5.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  said to be the Sariah GAINS (æ 64, b. KY) indexed in Bowling Green, Warren Co., KY (p. 73C).

6.  Email from Larry Hill.