Going to Japan for first time in October - Regional pass?

Thank you for helping!

I will arrive in Tokyo and then want to take the Nozomi first class to Kyoto. We are then going from Kyoto to Nara, Nara to Osaka, then Osaka to Fukuoka for a cruise.

Does it make sense to purchase the 5-day Green JR West Pass and upgrade to the Nozomi when we get there for the Kyoto trip and the Fukuoka trip? We are looking for first class and fast. Is there a away to pre-purchase the 5 day pass and the upgrades to the Nozomi?

We will only be there from 5 Oct to 10 Oct.

Please let me know if you think there is a better option! Thanks again, Shanin