Should you visit Wallace State in Hanceville, Alabama, you can easily spend several days there doing research. Their holdings are immense, courtesy of its director, noted Georgia historian and author Robert S. Davis.
As for "Georgia At Gettysburg" it is a work in progress, but quite aways from completion. I have a couple of much smaller projects I want to get published before wrapping up the bigger Gettysburg project, which I've been gathering material for since my 31st Georgia regimental was published in 1997.