All the previous comments are insightful, especially the one about the prior arrangement of the chair.
Here are some further thoughts:
* When she goes upstairs, Louise is both literally and figuratively elevated.
* The setting below the window -- especially the street below where the "peddler [is] crying his wares" -- implies Louise's position of relative privilege in her society. The workman (and it is a he) is out in the streets, trying to earn a living, while Louise has the ability to contemplate her future in comfort without Brently. This is not to criticize Louise; it is merely to state a fact about her relatively privileged economic status. Ironically, the workman in the street may actually have more psychological freedom than she feels she possesses because she feels confined inside her house.
* Louise's relatively privileged economic position in society is also suggested by the fact that she owns a "comfortable, roomy armchair."
* Meanwhile, note the fact that Louise sees
patches of blue sky showing here and there through the clouds that had met and piled one above the other in the west facing her window.
This imagery is more ambivalent than it might first appear. On the one hand, the glimpses of "blue sky" seem to suggest the possibility of a new and happier life for Louise. On the other hand, it is noteworthy that the clouds do not entirely disappear. Their continuing presence may imply that Louise's future is more clouded than she might like to hope.
Isn't it fascinating how much Chopin has put into such a short story? To go along with the astute observation of Mrs. Mallard's chair, the view out the window, the environmental setting, is reflective of Mrs. Mallard's inner moods.
The delicious breath of rain was in the air...she could see the tree tops....The notes of a distant song which some one was singing reached her faintly, and countless sparrows were twittering in the eaves.
There were patches of blue sky showing here and there through the clouds that had met and piled one above the other in the west facing her window.
Her new found freedom washes her feelings of repression away, and her soul sings. That there is a future is indicated by the tree tops that Louise can now see; the blue sky that appears is indicative of her hope for happiness now when before she has faced clouds of depression in the west, which always symbolizes death.
Another aspect of the setting that is critical in the development of character, theme, and plot is the chair that is facing the window. When Louise goes into the bedroom, the chair is already facing the window which suggests that Louise often goes to her room to look out the window (a symbol for her desired freedom). The placement of the chair leads directly into Louise's daydreams and eventual realization of the freedom she will have without her husband.
It is important to note that she goes down the stairs as her husband returns. There is an implication that she is descending to her demise, and maybe this is her pathway as penance for wishing her husband dead.
There was a feverish triumph in her eyes, and she carried herself unwittingly like a goddess of Victory. She clasped her sister's waist, and together they descended the stairs. Richards stood waiting for them at the bottom.
Very well said, mshurn. Inside the bedroom, she is restricted to her subservient role as wife. The other rooms of the house serve as a passageway to the great outdoors, where she can see freedom and the beginning of a new life. She exits the bedroom, enters the outer rooms and when the door opens, the outside world is within view. Unfortunately, her husband blocks her way once more.
The setting of the story shifts from the public area of the house to the bedroom. Once inside her room, "Mrs. Mallard' becomes "Louise,' a significant detail that contrasts her role as wife with her real personal identity. Sitting in her room, she experiences an emotional upheaval that culminates in truth: She feels free because she is out of her marriage, and she looks forward to the rest of her life. As this part of the plot is developed, Louise looks out her window and sees/hears the signs of spring. Thematically, this parallels her own emotional rebirth. When she leaves her room to go downstairs, however, she discovers her husband is alive, and she is thrust back into her married state. This reality is more than she can bear. She dies.