We left BC on 9/4 in the morning. We had seen on the news on Thursday, horrible video of I-4 back ups. Because the storm took so long to actually come, when we finally decided to drive our rental car home on Saturday morning (because it didn't look like we would ever be able to fly home in time for the kids to start school on Tuesday), we were the only people on I-4 and almost no one on I-95 until we reached Georgia. We were lucky and had great weather, but I was worried about something happening to our car and us being stuck on the side of the road with no one to help us. We went to the closed airport that morning to turn in our rental car and change to a new one way reservation to drive home (luckily, they let us keep the same car). The woman at National said that if we had turned in the car without getting a new one, she was under obligation to send us directly to a shelter.
From the advise of the front desk CM, I didn't check out of our room until we found gas in Jacksonville, which was before normal checkout time. She said that once we checked out, Disney would not be able to give us another room for the night. As long as we were still registered at BC they would keep us as long as we needed to stay, because of the hurricane. I called from the road to check us out of our room. A number of CMs also reassured us that Disney has their own water and electrical supply, so we would most likely have power and water.