Help working out which pass to purchase

Hi there
I am hoping someone could assist me with which pass/passes to buy for an upcoming trip.
We are a family of 6 travelling from Australia. 3x adults, 2x children and one child under 5.
We will fly into Tokyo and head straight to Nagano.
Once in Nagano we will spend a couple of days exploring the region within and then head straight to Osaka where we will spend a few more days exploring and travelling to and from Osaka and Kyoto. After that we will head straight back to Tokyo and spend a few days in Tokyo travelling within.
I understand that the passes are 7, 14 and 21 days. We plan on staying maximum 13 days. I have calculated the costs of individual train and bus trips we want to use, and it doesn’t seem as expensive as purchasing individual rail passes for everyone.
Is there another type of pass we can purchase to travel from Tokyo to Nagano to Osaka/Kyoto and back to Tokyo that might be not as expensive as the National pass as we don’t plan on travelling to other regions due to the time frame we are working with.
Thank you so much for reading and I hope you can help shed some light.
Bec