My dad was featured eight years ago on The Muny's YouTube channel to give a walkthrough of the percussion parts in West Side Story. If you've got a few minutes, it's worth the watch!
As the principal percussionist for 46 seasons, I think he played West Side Story five times. I was able to sit in the orchestra pit once at a rehearsal as a 20 year-old music student to follow the score and watch him play.
I got lost a lot, but he sure didn't!