Here in Germany, the name Kepplinger ("keh-plin-ger", and the "g" is like the "g" in "go", NOT like the "g" in "gentle") could also be written Käpplinger or Keplinger as they are all phonetically the same. However, Käplinger is NOT the same (it's "Kay-pleen-ger"). [Note to readers: pay attention to the "umlauts" over the "a"].
I wonder why there would be a record in 1730 unless someone was born or died in that year? I would hope that we'd get a typical record of a birth, baptism, marriage, or death that was earlier than the date of their departure. Hmmm...
Does the author of the book say anything at all about what sort of record we might see?
I will call in a few more hours to see if I can reach anyone in Schwaigern.