All I can say is another pilot and myself had a great time in C.R. We did a 12 hour Eco-Tour that cost $80. They picked up at the hotel, drove to one of the volcano's where we had breakfast and awesome CR coffee. From there, we drove to the rainforest where we walked a 3 mile trail. Saw around 4 or 5 waterfalls there amongst other things, and then went to a river tour. The boat let us view monkeys, snakes, crocs, and all kinds of stuff. I had a blast! As the other poster said, be careful of downtown. We ventured there during the day and didn't have problems, but our local driver told us its pretty tough if they know you're Gringo. Kinda hard to hide that fact!
Anyway, ask your concierge about the tours ~ I promise you won't regret it. Just make sure you bring a good quality digital camera.
American $ is okay, but I exchanged at the hotel for no charge...just make sure to spend it! Restaurants are okay...you have to really go off the beaten path to find the true local stuff. There's actually Hooters and Outback near where we stayed. Try to get a local driver, the taxi's are okay, but play the "No speaky English" when it works for them.
Enjoy.