Help me complete my Japan trip with some scenic views

Hi all,

I am 2 weeks into my Japan trip and currently in Kyoto. I've spent some time in Tokyo and next up is Nara/Koya san. I've about had my share of hightech neon city scapes, temples, shrines and zen buddhist gardens and really want to compliment my impressions so far with some nature/hiking experiences.

What I am looking for is some scenic views, some half/full day hiking, Ryokan and natural onsen. I do not want to be too far off the Shinkansen as I prefer not to spend full days traveling with the limited time I have left (about 1 week).

I am currently undecided where to go on March 24th, where I will be in Koya san, after a night at a temple. This is where I would pursue the above. I want to be in Tokyo on the 27th of March for the cherry blossoms, which leaves me with March 24th for transport, 25-26th free and 27th for reaching Tokyo, at any time of day. As you can see I have limited time.

I have considered Kumano Kodo and the pilgrimage routes/onsens there, but transport there seems too time consuming with the Koyasan-Tanabe bus connection not open until April 1st.

Another option I have considered is Ise-Shima, which lies somewhat convenient for the Shinkansen, but I worry it may be a bit underwhelming, but I haven't been there :)

Currently looking into central honshu area, which could be something like Tsumago/Magome->Nagano->Tokyo.

So, this is what I have come up with so far. Any one out there have some experiences/recommendations to share?

In advance thanks!