There is no community "Ranton" in canton St.Gallen - could it be a reading error and should be "Kanton St.Gallen"? According to Familiennamenbuch (https://hls-dhs-dss.ch/famn/index.php?lg=e
) Kuhn is a fairly widespread name in canton St.Gallen - let's look for Eppenberger - less common, and only Mogelsberg are places of citizenship for both Kuhn and Eppenberger ... a lucky coincidence, as the mother's name turns out to be Lenggenhager (not Eppenberger). Her son Jonas Kuhn was born 26.03.1823 and baptised on 27.03.1823 in the reformed church (Mogelsberg has also a catholic parish). Checking the death register I find the grandfather on 10.09.1850 (wich is 10 Sep - not Oct 9 ... note the difference in giving dates in English and German speaking countries!). Being sure now that we are looking for citizens of Mogelsberg, the Bürgerregister lists the entire family: I have transcribed this for you on https://www.geneal-forum.com/phpbb/phpBB3/viewtopic.php?f=62...
. According to this the father emigrated already in July 1848, the mother (and likely the children) followed in May 1849.
It would be nice if you could "answer" to this topic and post some information how the family got on in the USA (English is fine on the forum). This would have the advantage (for you) that as contributor you will be informed automatically by mail about new contributions, e.g. if someone reports information about earlier generations.