Hello, I don't have any specific information about the Georgia preaching circuit but there is an Electronic Edition of "The History of the Negro Church 1875-1950 written by Carter G Woodson and its located on the Documenting the American South site. There is also a book that is out of print that has some Photos of different early ministers, and some of them are from Georgia I will email a friend and get the name of that book for you.
Rosa Dawson