First of all, what a wonderful thing it is for you to have the diary! What a treasure! There are several ways to approach this.I usually work backwards inch by inch. Start with what you know and get the death certificates and try to search for the cemetery records.A lot of cemeteries are on line now. Since Joseph died in 1909, you should be able to determine where he is buried and get a little more info. from there.At a certain point, if you buried someone, you had to file a death certificate with the county where the person was buried. The cemetery had to file it.They also had to have what is called a "Burial Permit". Those frequently have information too. You may have to start with your grandfather and get his death certificate, and then you will know more about his parents.Is your grandfather living? I suspect not, but anyway you can also ask questions of the oldest person in your family. Starting at the other end of the line,I would want to know who else was in Cuyaga County, New York, in 1850.
Another thing you can do is get the actual Civil War Records, including the Pensions records, etc.You may find out Darwin's wife's name from those, if she applied for an extended pension after he died. You can get the Civil War records from your nearest National Archives Office or you can order them via the Internet, but that could be a little pricey.Also, cemetery records on Darwin might also include info. about his wife, etc. Do you know where he is buried.Is it inWayne County, Michigan? Zoe