The National Parks in Costa Rica offer established hiking trails. Since the idea of rainforest hiking is to see the rainforest, and preserve it as well, these hikes are laid out and marked by the park service, and in many instances the routes are improved by paved stones so you don't sink in mud and steps, handrails so you don't need to go hand-over-hand. In any of the National Parks and private parks you are not permitted to wander off the trail, as that creates ecological damage. This style hiking is usually 2-5 hours and travels in a loop. Along the way there will be sign posted points of interest. The type animals you will see is determined by how many people are using the same trails, and how quiet you can stand while waiting. By the way, some National Parks allow camping in regulated camping areas accessible by car. None of the National Parks allow real penetration for jungle camping in pristine wilderness.
Then there's the pure joy of walking slowly, standing still, and looking and seeing wonderful things. The sense of hurry drops away and the goal is purely to savor the surroundings. These hikes can be very short distances -- perhaps 2 kilometers in a silent cloud forest -- and take five hours to absorb everything there is to see, smell, hear, and sense. Cloud forests demand this type of intimacy, and "hiking" in a cloud forest is closer to tip-toeing than walking.