Visiting it in December 2014 to link up with our daughter who was completing study abroad.
We stayed in the small, quiet town of Quepos on the southwest coast. Preferring more local experiences, staying in an Air Bnb, rather than the westernized hotels in the upscale section. We also spent days wandering in town and in the national Manuel Antonio park, a bit of a tourist destination.
So, no zip lining for us. Just monkeys on the roof in the morning; Arenal - an
active volcano that was alas shrouded in clouds but made for an enjoyable rainy hike; at the tail end of the trip, a hairy but exciting drive in a rental car to the capital, San Jose, where a cousin lives. Thankfully we met him at the hotel - impossible driving!
Watch out for touristy areas - off the beaten path is best, if you like that kind of thing. Lonely planet has a good book.
By the way - we were surprised at the local gastronomy. The fancy restaurants tended towards Italian! If you research the history
and culture first, that could help be a guide. Many different regions and experiences to be had there. Have fun!