Travel in March 16

I am travelling in Japan for 2 weeks in March and wondered if anybody had thoughts about a stunning, off the beat, tour at that time of the year taking in beautiful (but not too expensive) onsen, lovely scenery etc. I have been to Japan many times and speak/read Japanese so can find my way around. I have been to most famous guide book places and all main areas including Kyushu, Shikoku, Hokkaido, Sado etc.

I was wondering about a week in Nagano and then down towards Iya valley in Shikoku and a day or two in Kurokawa onsen or Yufuin in Kyushu. Does anybody have any stunning recommendations or routes?

I will use japan rail pass but am not adverse to a few days in a car..

Thank you

Got to tell where exactly you have not been.
What you want to see: Mountains, Lakes, Coastal, Cliffs, Rocks, Architecture
Got to tell the dates and whether Sakura is your objective.

Go to places that the guidebooks don't cover. Most of the west coast is beautiful and interesting, and good to explore. For March I'm doing a mix of normal sights and some less usual ones, but each person has their own ideas about what is off the beaten path or not.

go nagano and make a onsen tour. this books has great recommendations: http://www.amazon.com/Nagano-Onsen-Guide-Day-Use-Springs/dp/1481214047 (even aside form most touristic paths)