Our family (2 adults, 2 teenagers) took the "Real Cano Negro" trip from Canoa Aventura. We had a great time. It was about a 2 hour drive from La Fortuna, with a stop at the Iguana Bridge, which was a lot of fun.
For the main event, your group goes in a small, covered, excursion boat (holds about 20 people) and cruises along the Rio Frio and then into the Cano Negro reserve.
On our trip, we saw a sloth, howler monkeys, an albino baby monkey, caiman, basilisks, lots of birds, and more. We really enjoyed seeing the jungle from the river.
Our guide and driver from Canoa were excellent. We definitely recommend them.