The characters Joost, Sarah and Jack represent the Cowardly Lion, the Tin Man and the Scarecrow from the Wizard of Oz. Each character has something in common with them. Jack is found near the stacks of hay and "hasn't had an original thought in days." Sarah, the Tin Man has a broken heart and has been searching for love most of her life. She also has a lot of mechanical device (metal) such as an i-pod and cell phone. Joost, is big like a lion but doesn't have the courage or the will power to stay healthy.
In an LA radio interview on "The Busted Halo Show with Father Dave", Emilio Estevez revealed that much of the inspiration he got for this film was the identical pilgrimage that his father Martin Sheen and his son Taylor Estevez made a few years before on the Camino de Santiago de Compostela in Spain. Estevez' son, then 19, fell in love, moved to Spain, and got married a few years later. Since that trip, Martin Sheen and Emilio Estevez spoke often of how they could make a film about the pilgrimage until an idea surfaced.
When one takes the 500 mile Camino de Santiago, they carry a scalloped shell with them as an identity. Emilio Estevez was given such a shell by a man who made that journey six times. When he made the journey while filming the film, he kept the shell with him.
After driving the length of the Camino with his young adult grandson, Martin Sheen initially suggested that a documentary be made to promote pilgrimage and honor the Camino. However, his son Emilio Estevez thought that an independent commercial vehicle would be a better way to go.
Tom (Martin Sheen) places bits of his son's ashes at various places on El Camino to signify that his son is making the journey with him. Though touching, this goes against Catholic teaching - cremation is allowed, but all of a person's ashes are to be kept together, in one place. Scattering or dividing the ashes is officially not allowed.
During the scene when the group is walking past a beautiful panorama of mountains, Jack is telling Tom about his dreams at Trinity College Dublin and they all share a laugh at Sarah's plan to lay her cigarettes at the feet of St. James - they're actually walking the wrong way. The scene was shot in the town of O Cebreiro in Galicia and the wooded path they appear to be entering would actually take them eastward back towards the Cruz de Ferro, not westward towards Santiago.
Captain Sebastian (the French police captain) refers to the Way of Saint James by its Spanish name "Camino de Santiago". As a Frenchman, he probably would not have called the route by that name. In French, the Way of Saint James is "Le Chemin de Saint Jacques." Since we are told his character made the pilgrimage a few times, it is possible that he might use the Spanish name.
Yorick van Wageningen plays a Dutch pilgrim on the Camino de Santiago in Spain. The Netherlands were a part of the Spanish kingdom before they fought the Eighty Years War to gain their independence. Spain and the Netherlands were also the final two nations in the 2010 World Cup, with Spain emerging the victor.
The trivia items below may give away important plot points.
According to the audio commentary on the US Blu-Ray release- The body in the morgue was supposed to be Daniel (Emilio Estevez). However, he could not be directing the scene and be in character in the body bag simultaneously. As a substitute, the part of Tom's son was played by Martin Sheen's grandson. Martin Sheen was not told about this substitution ahead of time in filming, so the shock we see on his face is genuine.
Martin Sheen did his own stunts for this film. In the audio commentary on the Blu-Ray, we hear director Emilio Estevez saying his dad did the stunts for the river scene. That river normally doesn't flow with that much force. The production company got permission to open the floodgates and cause the river to swell up to what is seen in the film.
There is a way that ends at the sea at Fisterra (about 80 km west of Santiago), called "Camino del Mar" (the Way of the Sea). However, the movie ends with the main characters in Muxia, a Galician village, 70 kms northwest of Santiago, next to the shrine of "Señora de la Barca" (a mystical place in Galicia, know for his miraculous stones and not being the end of the "Camino").