We did the canoe trip though Mayan Mountain Lodge. The drop us of somewhere on the river up Pine Ridge Road and we paddled until we got to the San Ignacio bridge. The price per person includes drop off and pick up. The pick up part is pulling the boat ashore after the bridge and walking to the cab company to get a ride back. The Mayan Mountain Lodge then pays the cab and they go to pick up the canoe later.
The trip is supposed to last between 1 and 3 hours. We thought 1 hour would mean brisk paddling and 3 would mean not paddling so we decided not to paddle much if at all. Even waiting under a tree until the rain passed us still brought us to the end in about an hour and 15 minutes. We talked with another couple and their trip took 45 minutes. So at a cost of $70 for two people (in 2004), and having to deal with the kids waiting at the dock to grab your stuff for money, it was not really the best deal. We would recommend asking a LOT of questions before you did a canoe trip and ask to see the map and gauge the distance and be clear about what 'pick up' really means. Different places offer pick up and drop off on different rivers.
A positive aspect of the trip is that we were on our own for a while without anyone else around. The river offered some nice photography and interesting birds and bats. The water was very calm so did not offer challenges that required talent or attention, allowing one to look around with binoculars and take photographs. There were no houses along the river where we went so it was just nature, nature, nature.