I checked mapquest using Des Moins airport as your starting point to Orlando airport and its 22 hours and over 1400 miles ( you would need to plus or minus how far you are from there). Thats a lot of driving to do staight through without being wiped out when you get there. Do you have more than a week? I MAY consider driving if I had a few days to make the drive there and back, but if I were just going for a week, I would fly.
We figure its cheaper for us to fly, but we figure it differently than other people might.
For a weeks vacation driving we would leave on Saturday morning, drive until Saturday evening and spend the night. You have gas, snacks, meals, and room for Saturday so I would
budget $200 for that day. You will have the same expenses for Sunday. Add the drive home on, and you are looking at $800 to drive not counting wear and tear on your car.
For a weeks vacation flying we leave early Monday morning, get there before lunch
and spend the rest of the day in Orlando. Going home, we leave late friday night. We use the weekend before getting ready and relaxing and the weekend we get back unpacking and relaxing so we don't start back to work tired.
Both ways you have 5 days in Orlando for a weeks vacation. If your plane tickets are less than $800 for all of you, I would say its cheaper to fly.