Sure, the ending is predictable. You know as it starts that this movie has a purpose. It wants you to experience being a pilgrim. You know that these pilgrims will have a spiritual experience and come away changed. To tell you this is not to spoil the story any more than to say that the boat sinks spoils "Titanic." It may be expected, but that does not diminish the journey.
Producer, director, and writer Emilio Estevez is not looking to keep the story hidden. The mystery of the story is not revealed in the events. It comes from the lives of the pilgrims themselves. It is a simple movie with depth, a complex character movie with a straightforward plot. As Dan Avery tells his father in a flashback early in the film, "You don't choose your life, you live it." This movie just might help you figure out how you might want to do that.