It has been a very long time since you posted this, but I, too, am working that line.
I have a little bit of information about Robert Thomas, but it is very difficult getting anything beyond his father and mother. I can't even seem to find them in the 1920 census.
Please contact me at firstname.lastname@example.org
and we will see if we can tackle this together.
By the way, Robert Thomas' brother Glen Monroe was MY grandfather.