This seems to be a reoccuring theme (not being nasty). I think we all want a magical wand to make the trip the great. I take the trip with the kids by myself regularly so traveling at night is NOT an option. And because of my eyes, I have had doctors limit how much time I can be on the road soooo.....
Here are 'my secrets.' I don't use the TV. I think that makes the kids worse. We stop every two hours. MANDATORY. Everyone gets out and stretchs their legs, play tag, whatever. MANDATORY. We will wake them to go potty. Every two hours, there is a new little surprise. (green army men, slinky, coloring book, new crayons. a book to read) Some of the surprises they have helped pick our, others are truly surprises.
We keep the snacks and drinks low in sugar. Mostly water now that the kids are a little older but some juices. No soda. It makes everyone need to stop more. Some cookies but carrots and celery and peanut butter, etc.
Eat a good meal at the end of the day.
GET A ROOM WITH A POOL.

Because everyone needs to get some physical energy out.
We have about 20 hours of driving so we generally make 2.5 days using the last 1/2 day to get groceries, unload, swim and maybe and evening out like the HDDR.
The biggest thing is to have fun. You are going to Disney. Start the vacation on the trip. No rush, no fuss, just fun.