POINT OF VIEW: The point of view probably would not change. In the story, the narrator is omniscient. In the movie, there would be no narrator, just action. The narrator in this story played no role except to tell what was happening, which is obviously important. The description: "Squares of light from farmhouse windows fell onto the blue snow" would have to be shown, not said. The ending would also have to take a much different approach. Instead of just saying that the men took a different turn, the film would have to somehow show it. Not having a narrator will definitely have an effect on the work, but it will not change the overall meaning of it.
CHARACTERIZATION: Characterization will have the biggest change of all the elements. Tub, Frank, and Kenny all need to be more developed. The audience needs to see the relationship between Frank and the babysitter and even his wife. And like mentioned before, we need to see Tub's struggle with food. Finally, Kenny needs to be more portrayed as the "evil" character who stole Frank away from Tub. This could be done through flashbacks of Frank's. Every time Kenny makes fun of Tub, Frank could think back to a time where he and Tub were better friends, ignoring Kenny. Adding details to the characters will create a better ending. The less sympathetic the audience is towards Kenny, and the more sympathetic the audience is towards Tub and Frank--the ending will seem more like sweet revenge, not a worry.
SETTING: The setting of the short story is perfect for the movie. But for the new scenes, for example, Tub's house, needs to be extremely modest to the poor side. His house needs to be unkempt with takeout and food wrappers all over the floor. This will help Tub become a more sympathetic character, because it will portray him as lonely.
I envision the time setting for this film to be in the nineteen seventies in a town similar to Martinsville. Because it is in the 1970s, there are no cell phones. They couldn't have just called up an ambulance. (Although they could have at the coffee shop.. )
THEME: The theme in the short story is the self-absorbency, but in the film I think the theme should be friendship. This needs to be about Tub and Frank "falling back into love", not romantic love, but friend love. Instead of viewing the scene where Frank and Tub confess their addictions to each other (Tub with food and Frank with the babysitter) as Frank enabling Tub for his own selfish reasons, the audience will see it the two men accepting each other for who they really are. This changes the actual meaning of the work. It will turn the film into a more "feel good" movie, despite the weird ending. The reunion of Frank and Tub will allow the movie to end eerily, because the attention of the audience will be of the other two men. The last scene will not even show Kenny. There will be a sign that shows which way the hospital is, and their truck will pass the stop. The camera will move in on Tub and Frank, laughing together and then zoom out to a long road into nothingness.