I've done the 10 day Island Panama itinerary twice and the Coral four times.
Highly recommend the ferry in the Canal - you go through the other two locks (Miraflores and Pedro Migueles) all the way over to the Pacific Ocean and get an entirely different perspective of the Canal.
I did a Princess Cartagena old city bus tour last November - very interesting.
I'm not much on shore excursions but really liked the ferry boat trip. Did the Limon river trip and found it boring.
You'll love the ship.