Doable or overly ambitious?

So based on Google maps its a 24 hour trip. That will require two 12 hour days of driving. By the time you add in fuel stops think you are looking at 15 hours a day. I, like you, can do 18-20 hours in one run, I've done it pulling a 24 foot cargo trailer. My wife on the other hand simply cannot handle more than about 10-11 hours a day on the road. It's not that she doesn't want to, like me she wants to get there as quickly as possible but can't handle that much time in the truck. I'll be surprised if your family can handle that much time in the vehicle at one stretch.