I have been to Costa Rica several times, but only on Princess and only to Puntarenas. But since Puerto Caldera is just slightly south of Puntarenas, I would assume that the tours offered would be quite similar.
Last trip we took what was called a "Mangrove Nature Cruise;" It was kind of like the Jungle Cruise at Disneyland, except for real. Very enjoyable. We saw many varities of birds, monkeys, iguanas and even crocodiles.
On previous trips we took the tour to San Jose, the Capital; and another time to the village of Sarchi. Both were wonderful, and a great way to see the beautiful Costa Rican countryside--although a bit long. But the local guides were very knowledgable and made the tours interesting and informative.