What's best value

Hi there,

Considering the change in JR costs I was thinking about doing some regional passes instead for an upcoming trip. It will be 2 adults and 2 children for 3 weeks in total. First week is passed in Tokyo then going up to Nikko where we were going to hire a car for a few days to end up in Kanazawa. From Kanazawa going down to Kyoto and Osaka where we will be for 7 days. While staying in that area we were planning on doing some day trips to Nara and Hiroshima and whatever else nearby that takes our fancy. Would we be best getting a Kansai-Hiroshima Area Pass for the last part rather than a full JR pass? Or is it more economical to pay as we go? Am not sure how the exclusions affect us, as have not been there before. Thanks for your help.