What part of Michigan? If Detroit, or Eastern Michigan, you'd be taking I-75 all the way down. I can help there. I live just off I-75 in Northern Kentucky, so I take that to Florida.
We have driven from MI to WDW many times (straight down I-75). It was tough when the kids were young, but now that they are teenagers it's easy peasy. On the way down we usually stop south of Atlanta for the night and finish the drive in the morning. We have done straight through, but with winter weather it can be tricky. Not to mention the arrival day is miserable after not sleeping all night. So most often we stop around Macon, GA. However on the way home we usually drive straight through. The vacation excitement is gone by that point and we just want to be home LOL.