It looks like your boys are about 9, 12, & 14 (based on your PTR). At that age, I let them decide what they want to keep them entertained on the drive. Our most recent trip to Disney was in June 2013 and my three youngest kids were 8, 13, & 14 at the time -- so, similar in age to yours. We have an 1,100 mile drive each way that we split over a 2-day period (12 hours on day 1, 4 hours on day 2). Things they chose to bring along:
MP3 player/I-pod touch
Tablet computer
Portable DVD players with a few movies
The 8 yo also brought a tablet and colored pencils, stickers, Bendaroos, and some small My Little Pony figurines.
I also had a "just in case" bag (that they didn't know about) with 2 new movies, a few trivia books, and a trivia card game. I didn't need to get anything out of that bag and I don't think they watched *any* movies. The older 2 listened to music most of the time and the 8 yo played a few games on her tablet computer in addition to listening to music. I made sure we had plenty of chargers (both for the car and regular outlets at the hotel), a headphone splitter (so 2 people could watch and listen to the same movie and the rest of us didn't have to listen to it), etc. so they didn't have any "down time" waiting for something to charge. I'm all about keeping everyone happy in the car.
As far as snacks, I bought several types of snacks (granola bars, goldfish crackers, trail mix, pretzels, mini cookies, etc.) and lined them up on the kitchen counter. I put out a box of the snack-size ziploc bags and told each kid to pack what they wanted for their own snack bags. They put their "little" bags into a big bag, wrote their name on their bag, and that was theirs to keep track of and ration throughout the entire trip. I had a small cooler in the car with bottles of water and juice.
I'm very happy to finally be past the point of having to pack the snack and entertainment bags for the kids (which I did for YEARS....my oldest son is 27). I always packed *way* too much stuff because I was never sure what they would want to eat or play with on the trip. Now that they do everything themselves, it's much more efficient.
ETA: We always play the license plate game. I print out the list from momsminivan.com and make sure I have a clean copy for the drive home. I date them and keep the completed lists in our Disney box. It's fun to look back and see how successful (or unsuccessful) we were in getting all of the states. It's always a thrill to find AK or HI somewhere along the drive.
