This is not a commercialized area at all. This means no gift shop, no museum, no snacks, no selling of guide maps. It also means the bathrooms are very, um, rustic. To be blunt, there are three stalls for women, you must potty with the door open, and toilet paper goes in the garbage can, not down the toilet. When you have buses of people unloading all at once, the limited quantity of toilets could be a real problem - especially when you consider the ruins are about 2 hours from the port town!
We did not even think about carrying an insect repellent on our cruise, but in Kuhunlich you're deep in the jungle and far from any cruise ship. Mosquitoes were plentiful here, but not overbearing. I did get a couple of bites.
That might not be a problem except for the fact that some mosquitoes here in southern Mexico are known to carry malaria. Having had malaria once - in the Philippines - I know it's not to be taken lightly and can even be fatal. I would strongly suggest that those visiting Kuhunlich carry an insect spray that contains Deet, and apply it before entering the jungle.