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.
On this level, it provides a good way for people to learn more about Afghan history and culture in the context of story. Looking at The Kite Runner as a story about culture, however, misses what the book is really about. This is a novel about humanity.