Dr Robertson said once there would be no Gettysburg if Jackson had lived. Confederate troops averaged 10 mi a day travel. Army of Shenandoah.. 25 mi. Jackson would have engaged in Schenectady NY or Bangor Me. by that time, LOL
Jackson was disengaged from the rest of the ANV during the Valley campaign in what was essentially an independent command. Had he been part of the Gettysburg campaign he would have had to have moved in conjunction with rest of the army. Further, Jackson had a serious case of the slows in the battle of 7 days. So, I’m not sure I agree with Dr. Robinson.