Very true, Baggage Handler #2, and, at the time, Sherman had a lot to be worried about. But, instead, he was so confident that he argued long and hard, in the face of the evident reluctance of Grant And Lincoln, actively seeking to change their minds about a plan that, at the time, seemed to border on madness.
From all that I can learn, the only source of real concern to Sherman was at the very beginning of his march, (when it was not at all a given that Hood would let him march to the sea without a major battle), relaxing only when he had advanced far enough Eastr, that it was certain that the AoT was not behind him.
In the end, the most important battle concerning the March to the Sea, was getting Grant and Lincoln to agree to it.