There are four major symbols in the poem used to represent death.
The Carriage represents the way that we are brought to the afterlife.
The Sunset represents the warmth of life (the sun) coming to a slow, chilling end.
The House represents the grave and the final resting place.
The Horses represent the foreshadow of death and the knowledge that your life is soon coming to an end.
These symbols help us understand her view of death as being a part of life, much like houses and sunsets.
Hope I could help.
