Tokyo-Kyoto-Osaka

Hi there, i just wanna ask simple things.
I will travel to Japan, this 2018 January, and will be visiting Tokyo, Kyoto, and Osaka
Since it will be winter, my friend told me to visit takayama (Shirakawa Go).based on her suggestion, i try to make my rough itinerary:
Day 1: arrived @Tokyo, go directly To Kawaguchiko
Day 2: roaming around Kawaguchiko, and back to Tokyo in the evening
Day 3: roaming around Tokyo (Odaiba, Ginza, Asakusa)
Day 4: going to Yokohama
Day 5: Kyoto
Day 6: Kyoto
Day 7: Osaka
Day 8: USJ osaka
Day 9: Shirakawa Go
Day 10: Kansai Intl Airport

So.. Is it better (and cheaper) for me to buy JR pass, and try to activate it on Day 3, or just go woth the ordinary ticket? Thank you