I don't know of any alternate titles for Sourwood Mountain.

Cripple Creek has several, include Red Creek, Going Up Brushy Fork, Shooting Creek, Pig Town Fling, Warm Stuff, and possibly others.

I don't know of any significantly different names for Cumberland Gap. Bascom Lamar Lunsford recorded a song called Dogget's Gap which sounds a lot like Cumberland Gap rhythmically but isn't quite the same. It's also related to "Bonnie George Campbell" and "Big Stone Gap" according to Fresno State's ballad index but I've never heard those two before. Also, Riding a Buckin' Mule Through Cumberland Gap and Big Stone Gap

Other names for Old Joe Clark are Betsy Brown, Vee Latty's Breakdown in A, Fare You Well, and Old Ely Branch