1b.  George W. Wagenseller.  1899.  Snyder County Marriages, 1835-1899.  Wagenseller Publ., Middleburgh, PA (available as facsimile reprint from HigginsonBooks.com):

p. 201	Rev. C.G. Erlenmeyer's Marriage Record...
p. 226	1859
p. 227	June 26, Isaac Kerstetter and Besny Strawser of Chapman twp.

Isaac and Bethany were both of Perry Township.

2.  1860 Census Images (online at Ancestry.com; Image #251 of 384):  Mount Pleasant Mills, Perry Twp., Snyder Co., PA, p. 554, PN 170, 1219/1269, enumerated 12 Jul 1860 (extracted by Diana Gale Matthiesen):

Isaac Kerstetter	24	m		Blacksmith	1000	150	Pennsylvania
Bethna    "	21	f					"
Henry     "	12	m					"
Solomon   "	67	m		Blacksmith			"
Barbara   "	61	f					"
Mary      "	15	f					"
Eli       "	22	m		Blacksmith			"

Solomon & Barbara are Isaac's parents.

3.  George W. Wagenseller.  1904.  Tombstone Inscriptions of Snyder County, Penna.  Wagenseller Publ., Middleburgh, PA (facsimile hard copies available from HigginsonBooks.com; online at the Snyder County PAGenWeb site):

p. 170	ARBOGAST'S CEMETERY. Located at Zion's Church 5 miles south of Fremont...
p. 172	Forrey, Simon, s of James and Bethany, b. Dec 23, 1871; d Mar 13, 1887, aged 15 y 2 m 20 d...
p. 173	Kerstetter, Hannah M, d of Isaac, and Pethany, b Oct 20, 1864; d Dec 11, 1865, aged 1 y 1 m 21 d. Kerstetter, Isaac b May, 7, 1836; d July, 2, 1865, aged 29 y 1 m 25 d.