Yes, Lee was over-all commander of CSA forces by then. I believe Sherman's army was around 60,000 at that point, moving as two prongs - one under O O Howard and the other under Slocum. Lee could have - if he successfully evaded Grant - landed on one of those two prongs and had a fairly equal contest. There was a wide separation between the two. Neither Howard or Slocum was a general to handle Lee. Of course, Grant wouldn't have just sat there wondering where Lee had gone! Getting caught between the two was not in Lee's best interest certainly. So, his best bet was to combine with Johnston. Hardee showed up in South Carolina, too, after the surrender of Savannah but his force was small. After Sherman completed his South Carolina campaign, he did combine with Grant as Johnston's army was disposed of after Bentonville. Lee was definitely toast then.