I just wanted the cenote visit, so I did the trip by myself without an organised tour. I took the Playa Express from Cancun then the collectivo to Tulum, 34MXN each. When I got to Aktun Chen, the man at the entrance called for a car to take me to the cenote, for free, as there are 4km through the forest. I paid around 300 MXN just for the cenote part of the park, which is much cheaper than the whole tour. The forest is beautiful, this was the season of blue butterflies, and you see lots of plants that are normally in a pot in the corner of an office. Apparently the staff pick and eat some of the jungle fruit. They don't do jungle walks for the public as they say it's dangerous.
The cenote was well organised, with lockers, clean environmental toilets, and life vest, as well as snorkeling equipment, shower and my own guide. I chose to visit this cenote because it's lit up inside, not dark as others, and it felt safer for me.
The guide was great, spoke both Spanish and English, and took me on a tour of the cenote. The water was cool but bearable. He showed me the rock formation, told me where to look underwater, which is breath-takingly beautiful as you see stalactites lit up, and took me to places where the sunlight hits the water from above and makes divine-looking rays you can swim through. You can see a couple of bats that eat fruit, and the fruit they drop underwater, roots and a bank of fish, but only in one place, as there aren't any other fish.
The best part is that at the end of the tour he left me to swim by myself in the cenote and there was nobody for 15 minutes, a moment of lovely solitude and quiet.