There weren't many Yeager's in 19th century Northampton.
I did find a death record for:
Charlotte Yeager b. Susqueanna (PA?), widow of Benjamin, died September 15th, 1849, age 53 in Northampton of dysentery.
(vol. 40, p. 110)
On the 1850 census for Northampton, there's a Benjamin, born NY, age 59, laborer. Daughters: Marietta age 17,
Charlotte age 15, both born in MA.
On the 1860 census, Benjamin is living with his married daughter:
Name: Benj Yeager
Age in 1860: 67
Birth Year: abt 1793
Birthplace: Massachusetts
Home in 1860: Northampton, Hampshire, Massachusetts
Gender: Male
Post Office: Northampton
Household Members: Name Age
Rufus Abba 27
Charlott Abba 25
Charles B Abba 2
Charlott I Abba 2.12
Benj Yeager 67
Maybe Charles was named for Charlotte's brother? Your Charles also has a son named Charles B on the 1860 census. The "B" may be for Benjamin.
Because your Charles resided in both NY and PA, and it looks like Benjamin was born in NY and maybe Charlotte his wife was born in PA where Charles S later lived, there might be a link there.
If you go to
www.familysearch.org and choose the record search pilot, you can download the censuses that Tina mentioned (search for Charles S) and also the 1850 with
Benjamin.
Good luck.
S.