At a normal walking pace, it would take around 20 minutes to walk around the 27-acre square field. If the 27 acres are in any shape more rectangular or irregular than a square, it will take longer to walk around.
Hosseni wrote The Kite Runner to show the world the way that common issues of identity, assimilation and power are carried out in his culture in Afghanistan. He spends a great deal of time developing Amir and showing how he comes to a self-identity by the end of the book.
Hosseini is much more interested in plot development and irony than in dazzling us with The Prose To End All Prose. And that's OK: his plot has the resonance of tragedy. Too present a writing style might distract from the plot. That said, we do want to point out a stylistic quirk in The Kite Runner. The descriptions often mimic the camera movements and cuts of movies. In an interview, Hosseini admits the book uses the language of movies but denies he intended to do so (source). Suffice to say, it's there.