21 Day Itinerary

We are planning 28 days in Japan in March & April 2024 and are looking at the green class service for 2 adults. We are starting off in Kagoshima and looking at the following itinerary:

Kagoshima to Fukuoka (Hakata) via Shinkansen on 3/22
Hakata to Yufuin on 3/24
Flying from Oita to Tokyo on 3/26
Local/regional travel in Tokyo/Nikko/Kamakura 3/26-4/1
Tokyo to Hiroshima via Shinkansen on 4/1
Hiroshima to Miyajima and return
Hiroshima to Kyoto via Shinkansen on 4/3
Local/regional travel in Kyoto/Osaka/Nara 4/3-4/8
Fly to Sapporo from Osaka on 4/8
Local travel around Sapporo
Sapporo to Atami via Shinkansen on 4/11
Local travel around Atami & Hakone
Atami to Tokyo on 4/13
Tokyo to Narita on 4/15

It's very difficult to tell online what the green class Shinkansen fares are, and we realize with the maximum JR pass being 21 days we will need to either get individual tickets or an IC card for the Kyushu portion the trip. We are trying to decide if it makes sense to each get a 21-day JR Green pass and activate it on 26 March or get a Suica card for Tokyo & Kyoto and pay the Shinkansen fares separately.