Although it's entirely possibly that the speaker is a hired laborer or that he's just a guy who's helping out his buddy down the road, our best guess is that the speaker is a man who lives on a farm with an orchard. If he lived in the city or even in a town, he probably wouldn't collect his drinking water from a trough every morning. In the early twentieth century, lots of people in New England lived on some kind of farm, even if it was not their primary source of income. We doubt that he makes enough (if any) money off of the apples to pay the bills. It's just something he does on the side. He's a very hard worker, but not a perfectionist. He's willing to leave a few good apples still on the branch when quitting time comes, though deep down he feels a little guilty about it.
The speaker's imagination is very active and drives him to look at the world from unusual perspectives, such as staring through a sheet of ice. Strange images tend to stay with him for a long time. A self-reflective fellow, you might say. He has soaked up some New England Protestantism and has read the Bible, but the emphasis on sin and corruption in the Old Testament seems to "trouble" him. Perhaps most of all, he's one bone-tired fellow. He may not sleep through the whole winter, but if you let him, he'd probably sleep for at least two days.