We watched prices and bonuses to try to get the best deal on any ship through the Panama canal and a few months out Princess gave us large OBC that seemed like it would be our best opportunity. I always continue to double-check as a learning tool for future bookings and did very well. We had not tried Princess yet although we have been on about 30 cruises.
This itinerary is terrific with all the stops: Aruba, Cartegena, Costa Rica, Nicaragua and Cabo. Plus the day passing through the canal is just one long shore excursion! The stops plus the canal plus movies under the stars (with popcorn) and the nightly entertainment and BOGOs in the afternoon with our favorite bar guy Kumar -- we had plenty to do. Get off at every port!
We took an organized Princess shore excursion in Cartegena (after reading the US State Dept warnings) and also in Costa Rica because I wanted to see the volcanoes. But did it on our own in Nicaragua (just mostly sat at a bar and then used that access to the ocean) and in Aruba where we walked the downtown area and in Cabo where we bought seats on a glass bottom boat to go see sea lions and get dropped off and picked up by that boat at Medano beach. Traveled with my husband and another couple.