Request for information

Hello,
I am travelling to Japan from 3/26 to 4/5. My itinerary is
1. 3/26 NRT airport to Asakusa Tokyo
2. 3/30 Asakusa to Nikko and back
3. 3/31 Asakusa to Odiwara/Hakone
4. 4/1 Odiwara to Kyoto [Booked Shinkansen]
5. 4/2 Kyoto to Osaka and back
6. 4/3 Kyoto to Nara and back
7. 4/5 Kyoto to Tokyo [Booked Shinkansen]
8. 4/5 Tokyo to NRT airport

Except the two Shinkansen trains i did not book any other trains.

Also I will be taking trains / subway in Tokyo.

I did not buy a JR Pass. Should I get one? Can I convert the amount spent on Shinkansen trains and apply towards the JR pass.

thank you
LK.