6 days in Japan - seeking onsen experiences

Hello,

I have the amazing opportunity to visit Japan for a second time! I am traveling for work and am planning to head out a bit early to explore new spots in this wonderful country. I'll have approximately 6 days of personal time. I'm looking for advice on where to go. I've done a ton of research, and I'm feeling a bit overwhelmed. On my first trip to Japan, I was able to visit Tokyo, Akita, Hakone and Kyoto. One of my favorite things to do is soak in an onsen. I like having a private onsen in my room as well as the ability to visit public onsens. I'm looking for advice on where to go this year. I'd love a town that has shops, restaurants and onsen! I also like to hike and didn't get to see Mount Fuji last time because it was covered by clouds. I have to be in Tokyo for work. I know I don't have much time so I'm trying to figure out what makes the most sense. Thank you for any advice you're able to offer because I'm currently going in circles with my research.