The wall is made of stones and functions to separate neighbors. It also holds rocks that were in the way for plowing the fields. "Good fences make good neighbors" was what the nieghboors used to say, but Frost doesn’t necessarily agree with building walls between people. The saying, "Good fences make good neighboors," is true to the extent that they give us boundaries. We need space. This saying is also false to the degree that they keep us apart and prevent intimacy.
"The Road Not Taken"
The poem literally means that the road forks and you must decide which way to go. There is also a symbolic meaning behind it. The two roads represent choices of life. If you choose the road not taken, then you are not being a follower, you are being your own person.
"Stopping by the Woods on a Snowy Evening"
He wants to stop and watch the snow fall, which he was afraid would be silly since it snows all the time. Sicnce he was in town, what would his neighboor think if he saw Frost. But then, what does his horse think about this unexplaned stop.
"And miles to go before I sleep" – Has two meanings. Literally it means that he must get home and symbolically that he has a lot to get done before he dies. The sleep he talks about is death.