Hi All, I am putting the final touches on our Japan Trip. It is our first time in Japan. We are a family of 8: the youngest is 16, and the oldest is 55. We have three weeks from early December and need to be back in Australia no later than 21/12.

Our current itinerary is 5 days Tokyo, 6 days Kyoto (including day trip to Hiroshima), 3 Days Kanazawa. We would then spend a day in Shirakawa-go on our way to Takayama, 2 days in Takayama, then onto Shibu for an Onsen experience 2/3 days. Should we skip Shirakawa-go and Takayama and go straight to Shibu, as this last bit of the trip seems messy, and I expect we will be tired by this stage? Question: Given our other destinations, does Shirakawa-go and Takayama offer something very different to our other stops, or should we skip this area altogether and add Kinosaki, Kurama or Amira Onsen earlier in our trip before or after Kyoto. Thanks for any input

Getting from Takayama to Shibu Onsen is over 5 hours by train and bus. That is too long, imo. By "2 days in Takayama" I assume you mean three nights there, so two full days. Less than that it is not worthwhile considering your second thoughts. Takayama does offer something very different from your other stop.

Shirakawago (like Gokayama) is a UNESCO World Cultural Heritage site. By definition and in fact Ogimachi, Shirakawa-go, offers something very different from anywhere else in the world. It has become very popular, but you will likely benefit by going there in December. You should find fewer tourists, maybe better prices, and the village will be quite scenic as it will likely be covered in multiple feet of snow.

You can visit Shirakawago on a daytrip from Kanazawa. The roads would be well kept clear of snow, at least for the bus drivers. Better yet, stay overnight in a gassho zukuri. I stayed at one that had snow boots available for guests.

You might experience the village like it is in the photo at the top of this webpage:Shirakawa-go and Gokayama Travel Guide
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You are going to need to make bus seat reservations as well as for trains in advance for a group of your size. Maybe you can rent a vehicle to accommodate your group. Hiring a driver can be done.

Shibu Onsen is certainly an attractive onsen town to visit (I have not been there). What is your plan for the 2/3 days? Visit the monkey park/jigokudani? IDK if you mean 2/3 nights or 3/4 nights but either way that is a bit long for a visit to an onsen town, ime, unless there is more to your visit than getting a soak and staying at a ryokan. It looks to be worth the trip from Kanazawa.
Shibu Onsen - Yamanouchi Travel

IDK about Kurama but Arima and Kinosaki Onsens are good options. Also, there are a few onsen towns near Kanazawa that are definitely worthwhile In Fukui prefecture, for example. In Toyama prefecture I did llike visiting Unazuki Onsen and the Kurobe Gorge. Unazuki is not a classic onsen town as Shibu appears to be. The train ride in the gorge will be very cold.

progol visited an onsen town in Fukui-ken in 2023, IIRC, so you could find her TR to learn more

I have not been to Arima but have visited Kinosaki Onsen - nice town with an onsen circuit but maybe too many Westerners (for me) there because tattoos are ok there.

If you're planning to visit Kinosaki, you can probably skip Arima Onsen—Kinosaki offers a much better onsen town experience. As for Shirakawago, it's absolutely stunning and definitely worth exploring in the winter.