Ok, here's what would be easiest if I were you (and good, don't get me wrong).
Write on Thoreau's WALDEN, breaking up and quoting from the sections. Here is what it would look like for me,
How did Thoreau influence the way modern authors use allegory, especially in reference to nature?
Many modern works have conflicted ideas of how man and nature connect. Hemingway's OLD MAN AND THE SEA shows the two forces opposed, while something like James Joyce's PORTRAIT OF THE ARTIST AS A YOUNG MAN ignores the role of nature and centers on the individual.
Many of Ezra Pound and T.S. Eliot's poems reflect alternative views of allegory and man+nature. This is where the modern use of "Imagism" comes in. That is, using the fewest words to explain very complex concepts. This goes directly back to someone like Thoreau who used nature to symbolize the most complex concepts of human existance.
I think you could get 4 pages out of this. With something this focused, you needn't freak out.