Travel from Shirakawago to Tokyo

Hello,
In the first week of December, I will be leaving Shirakawago at about 1pm. I only need to be in Tokyo at night. How should I plan my rides? A nice place to break and stretch the legs a bit....
Thanks.

It is a rather short journey these days. The obvious place for a break would be Toyama (or Kanazawa), as explained here:
http://www.japan-guide.com/e/e5953.html

Hi,
Thanks for quick response....
But would you think visiting the Castle at Matsumoto will be doable? Too Rush?

It is not along the way. And if you leave Shirakawago with the 13:20 bus to Toyama, you won't arrive in Matsumoto until 16:52, 22 minutes after the castle closes its doors.

I tend to agree with the above. Departing Shirakawago at 1pm wont leave time for any stops.