What a great idea Enchanted!
There are soooooo many Disney songs, it's hard to pick one...well..ONE has stood out for me. "Feed the Birds" by Julie Andrews (Mary Poppins). Not just a beautiful song and score, but a compelling story in many ways. It was also one on Walt's personal favorites.
Download the APP Sorcerer Radio and you'll get many more ideas.
You've inspired me to make some "USB" sticks for the vehicles. I wish I knew how to get songs from my DVDs and VHSs transferred to the mp3 formats.