The setting of the poem "Uphill" by Christina Rossetti is intentionally left vague because the journey in it is intended to be a metaphor representing a difficult activity with obstacles that need to be overcome. We can get an idea of what the author intends if we consider the expression "an uphill battle" to mean a challenging struggle to reach an elusive goal. The poem consists of a dialogue between two unidentified speakers; one of them is undertaking a difficult uphill journey while the other is attempting to provide reassurance.
The setting of a poem or story is the time and place in which it happens. This can include details such as the season, the time of day, the historical era, the weather, and so on. Not all of these specifics are mentioned, but if we take the descriptions literally, we can put together an outline of the poem's setting.
The only detail concerning time that we can infer is that the speaker asking questions is at the beginning of the journey. They are contemplating the road that needs to be taken, wondering whether it continues uphill all the way and whether there is accommodation to be found en route. The speaker who provides answers seems to have taken that path before and is confident in the advice provided.
As far as place is concerned, it is unclear whether the speakers are having this discussion at the bottom of the hill before the first speaker begins or whether they are walking the beginning stretch of the road together. We understand only that the road carries on uphill until the end and that there is an inn somewhere along the way where the first speaker will be able to rest and meet other travelers.