You are correct, Mary is probably not the wife of Harvey. I got her information from my GGGrandmother's Birthday Book and her name is mentioned as married (Mary (Biety) Bowie 1925 m. Sept 1924)
Of course this is after Harvey passed away.
The Prince is probably Princeton NJ.
Kearny is where his nephew, Knowlton Francis Pierce ended up later (Harvey is mentioned as Uncle in later obituaries) at probably the same mill and later became the Fire Chief of Kearny.
How Harvey met Mattie is a mystery, but thank you for this information as I did not have it! There is a Mattie Persius Pierce in the Birthday Book that was born Jan 21, 1862 which could be her. I need to inquire locally on this matter!
Somehow he knew Mattie who was likely in NJ at the time of the wedding and this probably brought him to NJ. Interesting...
I will post my family tree information (as stands now with errors) on cwnicholls.com link near the end.