If I am not mistaken, Wheeler's Raid of 1864 was not planned to go into Tennessee but, rather, hit the Western & Atlantic RR in North Georgia, rip up as much as possible and then return to the AOT in the Atlanta area. Wheeler succumbed to "JEB Stuart Disease" and rode his command right out of the Atlanta Campaign, accomplishing little other than wrecking his command. What was left of it made it back into Georgia to face Sherman on the march to Savannah.

By July, 1864, Sherman's supply line was fully tenable thanks to advanced supply depots (planned for 3-60 days of supplies in each) as he moved south towards Atlanta. The other factor is Col. William Wright's 3000 man RR repair brigade that did nothing but repair lines, rebuild bridges (the Chattahoochee River bridge, 750 feet long, was rebuilt in 4 days!) and the 1st Michigan Engineers made blockhouses everywhere. By this stage of the campaign no cavalry raid was really going to hurt Sherman unless it was from Forrest and Sherman made darn sure that he was stuck in Mississippi the entire time.

The other factor here is that when Wheeler left the AOT for this raid he left that army high and dry in terms of cavalry for recon and counter-recon duties. William "Red" Jackson's Division was all that was left to cover Hood's entire front and because there was not enough men to do so, Hood missed the details about Sherman's move to the west side of the city towards East Point and did not find out a thing until East Point was reached. Jackson was the best cavalry commander with the best division attached to the AOT but he was not superman.

Wheeler's 1863 raid into the Sequatchie Valley was much better at least in terms of being closer in and hurting the Federal supply wagons far greater than anything he did in his 1864 raid. This is all the more exacerbated by the fact that Wheeler had just had his finest moment as a cavalry commander when he smashed several of Sherman's cavalry divisions. Had he stayed closer in to the AOT after that time he could have been far more effective to his cause than what he did.

Greg Biggs