Martin Sheen originally suggested Michael Douglas or Mel Gibson for the lead role, but Emilio Estevez had written the main character's role specifically for his father and refused to make the film if Martin Sheen did not take part in it. During a screening of the film, Estevez turned to Sheen and said jokingly, "When Michael Douglas sees this, he'll fire his agent."
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.
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.
The characters Joost, Sarah and Jack represent the Cowardly Lion, the Tin Man and the Scarecrow from The Wizard of Oz (1939). 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 iPod and cell phone. Joost is big like a lion but doesn't have the courage or the will power to stay healthy.