My sister and her friends just got back from Costa Rica and the Tamarindo area. They flew into Liberia Airport. Based on recommendations I read about, they used Memo Adventures and Guillermo Espinoza - http://www.memo-adventures.com/ - for their transfers to/from the airport and for a couple of their excursions. They did the all day trip and one other trip. I HIGHLY recommend Guillermo's company for your transfers and tours. My sister said that he was absolutely wonderful to them. One of their group has a harder time walking and he aided her constantly getting in/out fo the vehicle, walking to the waterfalls, etc. He gave them great insights into the country and explained everything to them. Always on time, great service and everything they could have expected and more. Do not hesitate to use him for your travels. He is extremely responsive to emails, answering usually within the same day or next.