Given how happy she is with her two nickels, it seems safe to assume that Phoenix is quite poor. Also, she doesn't pay for her grandson's medicine; it is marked "Charity" by the nurse. Further, she wears a "red rag" tied on her head, rather than a hat, and wears a dress made of "bleached sugar sacks."
We know she has taken this path many times before because she knows the way by heart. Her eyesight has become poor, but she still can keep to the path. She says, "Up through pines . . . Now down through oaks." When she comes to the log laid across the creek, she says, "'Now comes the trial' . . . Then she opened her eyes and she was safe on the other side." In addition, the title tells us that the path is "worn," and we learn from the doctor's office that she comes every so often for the "soothing" medicine for her grandson.
She does seem accustomed to being alone, as she surmounts one obstacle after the next, without really seeming to be terribly set back. She does fall over once, but she certainly does not panic. Besides, she tells the women at the doctor's office that her grandson only has her, so it doesn't sound like she keeps company often.
I think she speaks to animals, just like she speaks to the scarecrow, because the world is so alive to her. She is quite aged and nearly blind, but she feels quite connected to the world around her, even being able to navigate it without the use of good eyesight. She is named Phoenix—a mythical bird who dies in flame and is reborn from its ashes—after all, and she seems to have some preternatural abilities herself.
Perhaps she imagines the boy offering her a slice of cake because he is symbolic of the promises made to African Americans after the Civil War, promises that were not kept. Likewise, when she reaches for what he's offered her, he disappears, along with the cake.
Phoenix does not have a real education. She tells the nurse that she "was too old at the Surrender" to go to school. She says, "I'm an old woman without an education." Her speech is simple and conversational, not polished, and this seems to confirm her report.