Irvin/Baer and Beyond

While my immediate family names are Irvin and Baer, my geneological search right now is focusing on the Harris/Courtwright branch of my family tree. My father's maternal grandmother was born in Tennessee in 1902 to Monroe Harris and Hannah Courtwright Harris. Unfortunately, Hannah passed away in 1904, so my information on her is limited at best. Also, I have no information beyond Monroe's parents, Jesse and Hannah Wells Harris.
I am currently exploring this side of my family due to the fact that there seems to be the most information about them. Finding it is another matter entirely!

Since I am new to this search and unfamiliar with tools other than word of mouth and old letters, any hints would be greatly appreciated!