My family drove down in August from Northeast Massachusetts.
One stipulation. I had to avoid major bridges and tunnels.
My wife has a fear of them.
So we took 84 to 81 to 77 to 26 to 95 to 4
In the car were : DW, DD (3.5), DS (.7), MIL, FIL and myself.
We left Friday night around midnight (I'll never do that again, but we were on a crash course with a hurricane coming up the coast

).
Our first hotel stop was in Roanoke, VA. at about 5:30 PM on Saturday night. Woke up Sunday morning, left at about 7 am and next stop was Daytona (beach) at about 7 pm on Sunday night.
Woke up early on Monday morning, my daughter got dressed in her tink outfit and we took about 1 hour to drive into Disney World.
This was our first time driving. Things that I've learned.
1. It sounds crazy, but even if you have your route planned out. Bring maps of the entire east coast. We avoided terrible accidents that had the highways stopped for hours by going around back roads, etc.
2. Consider the ages of your children. We were actually more concerned about 400 bathroom breaks from our recently potty trained DD (3.5) . She had no problems though. It turned out that our DS (.7) had issues nursing, etc. while in the car. So we had to make more than anticipated stops on the way.
3. Don't bring your in-laws (just kidding). Seriously though with two additional people who are not in the immediate family changes the dynamic of the trip. It ended taking us slightly longer, because we had more stops with the bladders of my in-laws and the nursing of my son. It's a consideration.
4. Everyone in the family truckster sounds good in theory, but in reality, although we had seating for everyone. There wasn't a lot of room and made the trip a little cramped.
5. Don't stay at LaQuinta inn in Daytona. They overbooked the hotel, and it was next to a "seedy" looking bar with poeple drinking outside. We ended up getting moved to the La Quinta Inns and Suites on Daytona Beach which were o.k.
6. If you are a "sleepy" kind of person at night. Do all your driving during the daylight. It was extremely difficult for me after the sun went down to maintain after many hours of driving. I wish I was built for it, but I am not. At one point I pulled over, and purchased 2 Starbucks Double expresso shots. (4 shots) to stay awake. I was desperate and it worked.
Other than that... It was great! Feel free to ask any questions.