In this poem, the speaker is familiar with his environment: he knows the woods and their owner (“Whose woods these are I think I know”: he knows the owner of the woods and where he lives: “His house is in the village”); in “My little horse must find it queer […] He gives his harness bells a shake to ask if there is some mistake”, the speaker interprets the horse's movements and behavior, which suggests he is familiar with him.
On the other hand, the horse “[asks] if there is some mistake”, being apparently not familiar with his present natural environment and being unsure about the route his master took, which leads the reader to think that the speaker doesn't usually go here, as the horse himself doesn't know this place.
In every stanza, Robert Frost uses at least one sense (visual/auditory): in the first stanza he “[watches] his woods fill up with snow” (visual); earlier the speaker says that because the owner of the woods lives far away in a village, he can go in the woods without being seen by the owner; the speaker is almost going against the owner just to watch woods fill up with snow. From this we can see that the speaker is close to nature and will face men just to contemplate nature's beauty.
In the second stanza, the speaker talks about a place “without a farmhouse near”, “between the woods and frozen lake the darkest evening of the year” (visual), in clear, away from everything; he speaks about a very mysterious scenery: no-one is around, the water which can represent life is frozen, all is quiet, it's the darkest evening of the year. The speaker is alone with his horse and the peaceful woods filling up with delicate snowflakes. He is away from civilization and in the middle of Nature.
The third stanza has mostly sounds: the bells shaking, the “sweep of easy wind and downy flake”. These sounds are restful, even the bells can have a soft sound; the “sweep of...