We plan to go to Karuizawa using the Tokyo Wide Pass. We are travelling from Shibuya to Tokyo Station, and then via Shinkansen to Karuizawa. How far and how many minutes would it take us to alight from JR Line to the Shinkansen Line? What are the track nos. that we need to take note for the right train to catch up to? With a limited no. of minutes to transfer from one train to the other, any suggestions on how we can overcome delays?