I believe that I have some of this in my database:

I have a Ellen Moriarty from Muingaphuca (which is also called Caragh Lake) who went to Philly to meet an Uncle Patrick Cahillane:

http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&d...

Her father was recorded as Jeremiah, but judging by her age and so forth, I'd say her father is your John.

Catherine MORIARTY
http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&d...
went to Philly to meet a cousin Foley. Her father Timothy is probably related to you family, as they are from the same townland. This might be the Foley link.

You mention John Moriarty and Margaret Cahillane's marriage date. Do you have the certificate? It mentions his father's name.

Bill