Chacchoben is the most practical Maya ruins trip from Mahahual. The site has restored pyramids, plazas, stairways, and shaded paths through the forest, with enough scale to feel substantial but not so much walking that the heat takes over.
It sits inland, roughly an hour from the coast by road. Cruise excursions come here in numbers, so independent travellers have the best chance of a quieter visit early in the day or outside ship schedules.