Matt, take a look at the photos, we saw monkeys, alligators, lizards, capybaras, and all sorts of birds. There are deer around too but we didn't see them. Its very quiet, not a lot of cars or trucks in Colonia Pellegrini. The hotel has Argentinian style power plugs and a very slow Internet connection via wifi in the lobby & restaurant. Contact the hotel about boats, tours, costs, etc.
My main piece of advice is don't try to drive there, the roads are terrible, especially if it rains. The hotel has a 4x4 and they'll send someone to get in you Posadas, Corrientes, or Mercedes.