Bob Nolan probably started the "Sons". He was an excellent songwriter, his tune
"Way Out There" is a yodeling classic.

The early actors in Hollywood for the most part were good musicians. Many were on the Broadway stage and some had legit singing backgrounds such as Vernon Dalhart.
He and Carson Robison set the stage for the singing cowboys commercially before Gene and Roy.

Gene got off of the ranch as soon as he could and never looked back. He worked as a telegrapher on the railroad before rising as a businessman.

Carson Robison actually had cowboy experience but not Vernon Dalhart, who took his name from prominent Texas towns.