When reading this book, you get a definite and distinct feeling about each of these settings. We follow Montag in the story, and in the city, he feels closed in, smothered, and restricted. This is because of the book burning, the mechanical dog which sniffs out the books, the loss of those whose books are burned, and the reaction of others in society when anyone mentions books, reading, or thinking. With the exception of Clarisse and Faber, Montag isn't able to really think out loud or discuss how he feels about his job and what he really wants to do--save the books and read and think. It is against the law, and the law is creating mindless buffoons like Montag's wife, Mildred, who sits and watches the TV walls of their house all day.
When Montag flees into the country, he does not have the comforts of home, but he is free to discuss, think, and share in the books these people know. They have each memorized a book to be put down on paper at a later date. They are intelligent people who are forced to camp in the wilderness to uphold the free thinking society values which were in place before books were burned.
In essence, the city is filled with fear, restriction, and the weak minded who allow these things to happen rather than stand up for justice and what is right. It is a dark place, where virtually no one is happy. They are policed by mechanical dogs and firemen who burn the books they own-- if they dare to own books.
On the other hand, in the woods are the free thinkers. The professors and the educated ones. The strong minded leaders of society have fled to live in happiness among like-minded people. They refuse to allow ideas to die, because they know that from conflict and debate comes the birth of still greater ideas. They are determined to preserve that for the future society, when it is again legal to own books and to read them freely. So, even though these people are outcasts of the city, they are happier, more free, and much more optimistic than those still living in the city.