Averil,
I don't have any other information re Robert Jacob Cain(e). I did not personally research this line but have noted the work in my database. Of course it needs further investigation to confirm. I believe that some of the info I got was on our genealogy message board.
The first information I got re Robert Jacob was from Shirley Hogensen of Utah who had researched the line.

A descendant in New Mexico said "They settled first in Chicago,
IL and then William bought a farm in central Illinois near Wyoming, IL and
Robert lived in Kane Co., IL. Their brother, Thomas, had two sons who came
over to the U.S. also, namely Philip Caine and Thomas Caine. That family
added the "e" to the name because they did not want to be associated with
Cain who killed Abel (family tradition states this anyway)."

Hopefully, Liz's ancestor can be found.

Donna