All answers are great. One thing to add is that the car parking has people who monitor the cars for tips (something that happens a lot around Costa Rica) I would always tell them no problem but I would only tip when I got back. This way they actually are around and dont just leave whenever they want.

40 metros

Not sure about the Zip line. There is not much at Playa Avelenas. The airport is about 1 hour 45 mins away, and the roads are not all paved into the beach area. I would definitely stop for groceries on the way in, to stock up.

Sorry if you already got your answer. If you’re passing by any of the major towns like Tamarindo or Santa Cruz, stock up there. Near Tamarindo at Villa Real is a great fruit stand. The two supermarkets near Villa Real north and south of the town are cheaper than the pricey Auto Mercado.

When you arrive on the beach, in front of Lola's restaurant, you have to go to the right for 500mt. You have to looking for it because is hidden from some trees. There begins the manglar path that ends in Cabinas Las Olas Hotel. It's a free passage.

I don't know . We were staying in Tamarindo and drove around. If you stay in Tamarindo you can walk to the beaches.

I would recommend contacting Iguana Surf they are in Tamarindo. They can rent you a board and make arrangement to get you there, they can also provide you an instructor if you wish. I would suggest staying in Tamarindo, there is a lot to do and it has nice waves to get your feet wet again (if it has been a while for you) then head out to Avellanes as a day trip (as mentioned by another reviewer). ENJOY!

If you want go to Playa Avellanas from Tamarindo you can take the Avellanas Express Beach Shuttle in front of Neptuno Surf Shop, next Agua Disco, with 12$ roundtrip. You can check the schedule in Facebook Page 'Avellanas Express' . Pura vida