Last evening I quickly surveyed the contents of the "MUSSELMAN" family file folder at the Lanc. Co. Historical Soc., scanning for info on David Musselman of Manor Twp., since your message suggested that he may have lived in that township. I found nothing but I will look again based on what follows.
I visited the Lanc. Co. courthouse archives but was unable to find a will for David Musselman. However, I did find some Orphan's Court records pursuant to a David Musselman of East Hempfield Twp. dying intestate leaving a widow Susanna and six children. I believe this is the David Musselman in question.
It now appears to me that Susan(ana) Musselman was probably the daughter of Johan George SCHMELING (SCHMALING/SMALING)[1780 - ?] and wife Elizabeth [1782-1853]. Their daughter, Susan(ana) was born April 26, 1812 according to the records of Lancaster's Trinity Lutheran Church. She then would have been about twenty if she married David about 1832.
I suspected that John Smaling (SNELLING), guardian of David's daughters Susan and Mary (as of June, 1848), was the brother of Susan Musselman. However, the U. S. Census of 1850 does not include Susan and Mary as members of brother John's household. The girls were listed as "minors under 14" in April, 1848 but it is possible that they could have been old enough to be boarding elsewhere (as hired help ?) in September, 1850 when the census data was recorded.