I had the good luck to correspond with German genealogists who have traced the Peppler family. It is such a (relatively) small family that they were able to find my ancestor, Johann Phillip Peppler b. 11/17/1822, who emigrated from Hesse Darmstadt to Baltimore c. 1848, on their family charts which trace the Pepplers back to 1618. I have some but not all of my information at this website:
There are other Pepplers in Baltimore to whom I cannot make any connection - the names Adam and George, for instance, don't appear in my family anywhere. None of our Pepplers went to Pittsburgh. They all stayed in the York County PA/Baltimore and Carroll County MD area.