Hubby and oldest son did the Los Des Vernos Canopy Tour (an independent tour) for $71.50 each (plus $6 for taxi fare) and had a wonderful time. They booked theirs for 11AM (which gives the ship time to dock without you being rushed since PV is an hour ahead of the ship).
They booked it on line, but did not have to give any credit card info to hold the reservation. You simply pay cash (or Credit Card with a 5% surcharge) when you get to the office.
They were able to swim after their zipline tour right there where they finished the tour in a little river by the restaurant.
Just another option to consider!
Have a great cruise.