Sorry, there is a catch: I'm not actually an old man, i just want to live the life of an old man in a shack. What i really want is to maximize the hours per day dedicated to sleep and whatever else i want to do, which currently is only reading and writing. I had a relatively bad undergrad GPA and basically want to live the life of a professor without having to worry about grad school, then phd, tenure, teaching if i don't want to, meeting with people i don't like, etc.
If I remember correctly, Joseph Campbell waited out the Depression this way. I don't know how he supported himself (probably borrowed the cabin from family), but he basically read books for 5 years.
And what he discovered during those 5 years was really grand. Do you have a reference for his auto/biography ? I know he ran track at Columbia, manage to visit Europe and learned sanskrit.