I did find a little bit more about his home that was turned into a nursing home today, which is a PDF document that I am in the process of translating via Google Translate (I am sure that there are better/quicker/easier ways) but I wanted to get a jump on it and see what it says. Additionally it also provided a new photo of Adam's wife.
I am still searching for documentation of his birth or anything about his parents. FamilySearch has his birth as 1842 to to Lorenz Hopfengartner and Maria Zacker, on secondary site it is stated as December 25, 1842 in Nuremberg, Germany.
We know that he was married 30 May 1971 in Westfalen, Prussia per his FamilySearch to Wilhelmine Huettemann (another brick wall for another day). Additionally we know that he had 8 children, ran a successful company with stock options, and passed away 25 Oct 1918.
I have searched on FamilySearch for anything Hopfengartner in Germany for the time period of his birth or his parents name but have come up empty. I have also searched anything on Google for the names of his parents. And while I know that I am only doing internet types searches I am limited because I live in San Diego.
If there are microfilms that I should get, or other websites that might be of benefit please let me know.