It seems too introspective and too unplotted to be made into something as literal as a movie. The setting is Texas in 1949. America has not yet completely entered the modern age, and in the ranchlands of Texas, especially, things are still very much the Old West.
Horses are the primary means of transportation.
The time seems so far distant from 2001 that when things like cars and telephones are mentioned, they seem anachronistic. We have to remind ourselves that yes, those things DID exist at the same time as these cowboys and roughriders. The three make it to Mexico, where Jimmy's horse and gun are stolen. John and a slightly more reluctant Lacey are willing to help him get his property back, but Jimmy impetuously rushes the place, drawing attention and forcing John and Lacey to take off, leaving him to settle his own mess. Here is where the film stumbles a bit, changing from a drama about a man searching for his soul into a fairly standard forbidden-love thing.