All major airlines fly into the capital. From there you can catch a puddle jumper. Sansa flies to Manuel Antonio/Quepos. totally worth the $. Beautiful view and only 20-30 min. Vice the LONG bus or taxi ride.
you can catch a bus from the capitol for $4-5. and it will be an adventure I am sure, becareful of Pick Pockets at the Coca-cola bus terminal in San Jose.
You can also rent a car I would recommend a 4 wheel drive. the roads are not well marked and very curvy and winding with steep cliffs at times
