My wife and I are on the Island Princess and will be in Costa Ricaon the 23rd. We booked a 7 hour tour through okeydokeytours.com They seemed to be well recommended. It's $99 for the B-4 tour which includes
Caldera Forest to see the Cappuchin monkeys, Mango plantation, Vilal Lapas canopy and rain forest where you have one of 4 options 1.zip lines 2. horseback riding, 3. crocodile river cruise or rain forest walk. then it's on toTarcoles town to see scarlett macaws, toucans and iguanas. On to Jaco beach for a supplied Costa Rican lunch. next the bridge to see crocodiles on shore, the ocean and waterfalls. Finally into the city for coffee and vanilla and souvenir shopping. Hope this helps
I cannot make a specific tour recommendation since I do not know what Princess offers. However, I will add that I highly recommend that you do something that gets you into the country. Costa Rica is a beautiful country and you do not want to waste this opportunity by staying on the ship, or just walking around the port area.