I really enjoyed this trip. We arranged the tour from Hotel Los Lagos for about $50 including tour/guide/lunch. Our guide was wonderful and extremely knowledgeable about what we were seeing and also answered general questions about life in Costa Rica.
An hour into the trip, our driver spotted a sloth hanging from a tree on the side of the road. I was thrilled! We continued on and stopped again to watch iguanas lounging in the sun. Arriving at Cano Negro, we boarded a boat for a 3-hour ride on the river (the one that can take you into Nicaragua). This was the best experience with wildlife I had in the country. It was probably my favorite part of the trip. From monkeys to birds to lizard (and more sloths), we really got our fill.