1a.  Jordan R. Dodd, ed.  1993.  Georgia Marriages: Early to 1850.  Liahona Research, Orem, UT (Broderbund CD-226):

Stroup, Joseph

Johnston, Mararet (sic)

21 May 1849

Cherokee

1b.  LDS.  Family Search: Internet Genealogy Service:  IGI - International Genealogical Index (online at FamilySearch.org).

Joseph STROUP Spouse: Margarett JOHNSTON Marriage: 21 May 1849, Cherokee, Georgia Source: Marriages, 1841-1910. Georgia. Court of Ordinary (Cherokee County)

2.  1850 Census Every-Name-Index/Images (online at Ancestry.com, Image #42 of 280 — indexed "Straup"):  Division 15, Cherokee Co., GA, Roll M432_65, p. 423B, 289/291, enumerated 10 Aug 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):¤•

Joseph Stroup	24	M		Farmer	100	Ala
Margaret  "	23	F				SC
Mary A    "	1/12	F				Geo

3.  1860 Census Every-Name-Index/Images (online at Ancestry.com, Image #6 of 19):  Fosters Mills P.O., Fair Play Dist., Cherokee Co., GA, Roll M653_116, p. 719, PN 59, 424/440, enumerated 16 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):•

Joseph Stroup	32	M		Farmer		30	Alabama
Margarett "	33	F					South Carolina
William H "	13	M					"
Polly A   "	9	F					Georgia
Sarah E   "	8	F					"
James B   "	6	M					"
Amanda J  "	4	F					"
E A       "	2	F					"

I cannot find William in the 1850 census, not with surname STROUP (or variation).  Has he been adopted?  Is he William GILSTRAP?

4.  1870 Census Every-Name-Index/Images (online at Ancestry.com, Image #32 of 97):  Pine Log P.O., Subdivision No. 144, Bartow Co., GA, Roll M593_135, p. 515B, PN 32, 236/236, enumerated 26 Jul 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):•

Gilstrap William	18	M	W	Farm hand			Ga
Stroup Margaret	40	F	W	Keeping house			SC
______ Eliza A	9	F	W				Ga
______ John E	7	M	W				Ga
______ Sarah E	15	F	W	at home			Ga
______ Mary A	19	F	W	"   "			Ga
______ James B	14	M	W	Farm hand			Ga
______ Mandy J	13	F	W	at home			Ga

Margaret appears to be fibbing about her age.  I have no explanation for the ordering of the children.  It's a near certainty that William is boarding with Margaret, but the sexism of the enumerator does not allow him to make a female the head-of-household.

5.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  not found.

6.  Edmund West, comp. 2000.  Family Data Collection.  MyFamily.com, Inc., Provo, UT (online at Ancestry.com; n.b., West is a secondary source):

Name	Date of Birth	Place of Birth	Date of Death	Place of Death	Name of Father	Name of Mother	Date of Marriage	Place of Marriage	Name of Spouse
Eliza A Stroup	1861	Morgan CO, AL			Walter Bedford Stroup	Margaret
John Edward Stroup	1863	Morgan CO, AL	1938	Chatooga CO, GA	Walter Bedford Stroup		1885	Bartow CO, GA	Nancy Savannah Kembrele/Kimbrell

Eliza and John Edward are the children of Joseph & Margaret (JOHNSTON) STROUP, not Walter B. & Margaret (PEEPLES) STROUP; and they were born in Cherokee Co., GA, not Morgan Co., AL.