Is it suitable for people with no past experience in Snorkeling? Do you have pickups from The Reef 28?
Everyone has a first time snorkeling, and the guides will help you put on equipment. None of the stops is scary. I have done this trip 3-4 times over many years. Whoever picks you up will be with you the whole day. By the time you reach first stop, by chatting in the van he will know who might need help. Since there are numerous van loads daily, the stops may be in different orders. The open cenote and cave are not too strenuous. Yal-Ku lagoon is big. They will offer to keep you swimming over an hour, but you can quit earlier. Enjoy!