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

Thompson, William W.

Long, Nancy S.

7 Dec 1826

Christian Co.

2.  1830 Census (extracted by A. Robert Matthiesen; see 1830 Table):

1830

William W. Thompson

KY

Christian Co.

p. 6

Hopkinsville

100 010 - 100 100

These data indicate

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	4 or under	1825-1830	= Son A
1 male	20-29	1800-1810	= William (b. 1803)
1 female	4 or under	1825-1830	= Daughter A
1 female	15-19	1810-1815	= Nancy (b. 1811)

They are living next door to John Slaughter LONG, Nancy's brother, who is living next door to Lucinda (SLAUGHTER) LONG, Nancy's mother. 

3.  1840 Census Index (online at GenealogyLibrary.com):  not found.

4.  1850 Census Index/Images (online at Ancestry.com; Image #136 of 137 — indexed as "Nancy T.J. Thomson"):  District No. 1, Christian Co., KY, p. 497B, 955/1021, enumerated 19 Oct 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):

Louisa A Steele	42	F			Ky
[Louisa's children]
Nancy S ? Thomson	39	F		1500	Ky

Louisa (THOMSON) STEELE is Nancy's also-widowed sister-in-law.  Nancy's initials are difficult to read, but they are definitely not "T.J."  The first initial is definitely "S," and the second one could be "L." 

5.  Messages in the Long Family Genealogy Forum (online at GenForum.com).

6.  LDS.  Family Search: Internet Genealogy Service: Ancestral File and International Genealogical Index (IGI).