We took Nature Air from the capitol San Jose to the coastal city of Tambor which has a small airfield, to get to our house in Mal Pais, another 45 minute taxi ride from Tambor. Nature Air has a website where we booked our flight, and even though they changed the times a couple of times, all in all it was an easy, good experience. The planes are small but comfortable and the wind was minimal for our flights. They are very strict about passengers being at the airport at least 45 minutes before the flight leaves. Nature Air leaves from Tobias Bolanos Airport in San Jose.
There was, at our time of arrival, a fee of $2.25 each paid to the guy asking for it when you get off the plane in Tambor, and we also had to pay it when leaving.
I hired Kevin via the Alamo Rental storefront in Mal Pais, and was very pleased---he picked us up at 6:30 am tight on time for the trip to Tambor for our flight to San Jose. $50 for the trip in a nice van---real nice guy and recommended.
The best way to get around Mal Pais is just to walk, nothing is far, but if it is a bit further along the road, hitching will work fine too.
And if really tarveling to other places, a bus or cab is the way to get around.
And if you want to come here with your own transportation, make sure it is a 4WD, otherwise you could get into lot's of trouble.
To get to Malpais the best thing is to get the boat from Puntaneras, and then either take the bus ( a long bumpy ride) or share a cab with other travelers (otherwise it will be expensive).
We had luck with the cab, had a great guy driving us to Mal Pais, who stopped whenever he spotted some monkeys.