In simple words it is a metaphor for life. Kafka on the shore doesnot have a rational standpoint neither a logical plot line. Many questions might arise as you read through it, but your answers might not be answered.
Rather you need to decipher the metaphor it potrays.
If you want a novel that gives a new perspective of how you see the world and your life, go for it. Carve your way through the labyrinth of the plots and find a meaning original to your thoughts.
"You will be in a brand new world after it".