According to several sites, Happy Sunny Side of Life is by Bill Bolick of the Blue Sky Boys. They certainly recorded it it 1936. However, this site gives it a date of 1918 and attributes it to J. Wesley Watts, refrain by Tillet S. Teddlie, according to The Gospel Trumpet Company, Reformation Glory, 1923 (12).

Hoping that the book would be available online, I Googled

          "reformation glory" songbook

Although the book itself does not seem to be available online, one of the search entries was the following:

          Classic Country: Legends of Country Music
          books.google.com/books?isbn=0415928273
          Charles K. Wolfe - 2001 - ‎Biography & Autobiography
          "Sunny Side of Life," recalls Bill, was taken from a songbook called The Reformation Glory, which was a hymnbook used by the First Church of God. "I heard it ...

Classic Country isn't available online without buying it. Nonetheless, it does support the first site's attribution for the song's origins.

I cannot find any information about the first author, but the second appears to be a typo and in fact be this man: Tillit S. Teddlie.

BB,
NightWing