I think he’d get a kick out of Indiana Jones. Reasons for this: a) it’s a motorized vehicle, b) it cinematically progresses in an immersive manner c) the animatronic Indy is pretty good and d) the queue is incredibly immersive and has a lot of interactive elements
Maybe Toy Story Mania, he liked the idea that rides had new experiences for the guest and I think he would like the 3D aspect and the interactiveness. I could totally picture Walt trying to get the best score.
Radiator Springs Racers. The whole Carsland area brings the movie to life, the drive through the canyon at the beginning is beautiful, there's a story in heading into/going through town, and then you have the minor thrill ride of the race with variable endings.