Day 1: Arrive Narita Airport and stay in Shinjuku Gracery Hotel
Day 2: take JR Chui line from Shinjuku to Otsuki, then get on Thomas train to Fujikyu
Day 3: From Shinjuku to Karuizawa
Day 4: from Karuizawa to Shinjuku
Day 5: Shinjuku to Ueno Zoo
Day 6: Shinjuku to Narta airport
Question: pls suggest if any JR or metro pass that I should buy to save my cost in transportation