My name is Ron Penland. I have quite a few records on the Penlands all the way back to the 1700's. I do have a record of a George Penland (1753-1829) who did die in Buncombe County and did have a son named William, but his wifes name is listed as Comfort Adeline Mull, however, George's Brother, Robert(1744-1828), also had a son named William who married a Mary Polly (maiden name not given? Just written as Mary Polly Penland). There are two G.W. Penlands listed in my records(One was my great grandfather and the other was his cousin). Unfortunately, neither of thems mothers name was Mary. My ggrandfathers mothers name was Nancy A and his fathers name was Robert C Penland and the other G.W. Penlands mom was Patience M and his dad was H.M. Penland, Robert C.'s Brother. Their fathers name was also George(1778-1877), who was the son of Robert above..
Having said all of that and probably getting you confused, do you think maybe George's brother, Robert, is the one who had the son William who married your ggggrandmother, Mary Casey? His wifes name is listed as Mary Polly Penland? As for the G.W's I know my greatgrandfather, G.W., didn't have a daughter named Mary Jane-don't know about the other G.W but his name was George Wiley according to records I have and his moms name is listed as Patience Moore. Maybe Robert's son William had a son named G.W? Seems the Penlands pretty much stick with the same names for their kids?LOL
Maybe if you research Robert Penland(4/22/1744-4/16/1828) you can find the info you need? You can contact me at firstname.lastname@example.org
if you have any questions about this? Be safe
A couple of footnotes to keep in mind:
1. According to the records I have, the Pentlands migrated to NJ and PA from Scotland in the 1600's. Some time after they arrived in America, the "T" was dropped from their name.
2. Three of the brothers (George, Robert and William(1745-1815) migrated to North Carolina (while at least some part of TN was still NC) to start the Penland name in that state so if you research those three names, you are bound to come up with the info you are looking for..
Again this is based on info I have received from other people as well as research I myself have done.