On my second day at Corcovado Park, after a day on the beach accompanied by monkeys and birds, I had to cross one of many rivers. And after several days of rain, it was pretty rough and quiet an effort. I had to pair with a companion for safety's sake. We walked through the jungle for about 4 or 5 hours, taking advantage of the fact that we were the only human beings in this preserve. We looked for pumas and jaguars, kings of the park, before realising the truth that we were alone and defenceless! With with the help of the tides we crossed other river and entered the rainforest. It was extremely wet and difficult to put together the tent at night. In the camp we weren't able dry anythin, noor could we prepare hot food being short of electricity and gas, but after awhile the local guards let us boil some water for pasta. Everyone comes on foot too, and with loaded backpacks, enough to spend 15 days! You will be able to point out where animals were last seen, and how best to cross the rivers, as well as how to best to enter and exit the park. If you change your itinerary, as we recomment, you will make friends you never knew before.
I was in Costa Rica a couple of years ago and Corcobado Beach was an incredible place to discover. The area of the Pacific was home to the beaches I liked the most, like Montezuma Beach and the natural park of Manuel Antonio. 100% recommended!