By collectivo in the dry season, it takes 2-1/2hrs or more depending on stops etc. By taxi, it should only take 1-1/2hrs. You can also fly on AlphaRomeo (Alvaro) from Puerto Jimenez to Carate in about 10 minutes.
Walk. There is a thirty-five minute walk along the beach between Carate and the entrance to Corcovado at La Leona Ranger Station.
There is a small snack stand, but people who are entering Corcovado through this route should make sure that they purchase food in Puerto Jimenez to bring into the park.