Cancuén was a major trading center in the Classic Maya period.
Flora and fauna
A minivan and a passenger pickup provide transport between Raxrujá and La Union, the village from which you can arrange the boat to the ruins themselves. As of February 2007, the boat cost 300 Quetzals. You need to arrange the boat from the tienda nearest to the entrance sign. Following the sign pointing to the embarcadero will just get you a nice view of the river and a longish hike back to the tienda.
60Q each to get in.
The site has wooden walkways for seeing the palace and other parts, so mus in unlikely to be a problem there.
Head back to Raxrujá.
There is plenty of camping space available at the site.