Our favorites for Disney road trips are the Kingdom Keepers on audio; the kids really like those, and so do we.
If you want nonfiction, and if you are interested in the history of Disney's technological innovations, you might enjoy The Mouse Machine: Disney and Technology (note that this was published in 2008, so it doesn't cover such new developments as the Magic Band system.)
If you are childless on the trip and in a contrarian mood, you could try Carl Hiaasen's Team Rodent: How Disney Devours the World. Hiaasen is relentlessly anti-Disney, but he's also a native Floridian and funny as heck, so if you can take the anti-Disney rants, it can be a good read. Hiaasen has a background as an investigative reporter, so he does have facts to share; it's just that his interpretation of what those facts really mean is rather different from those of the average Disney fan, LOL. (We greatly enjoy the circus that is Florida politics, so we like Hiaasen, but I know that not everyone does.)
You also might want to consider books about Florida. I don't know about you, but LMAO makes the trip go MUCH faster, so I'd also like to suggest Dave Barry's Best. State. Ever.: A Florida Man Defends his Homeland. Barry is less caustic than Hiaasen, so he's a lot more popular as a humorist. He reads his own audiobooks, so you get his reading talent along with the funny stories.