Most beautiful route from Kyushu to Osaka by public transport?

I'm currently in Kyushu and would like to reach Osaka in a few days, preferably by train (but short bus or ferry rides are ok). On the way, I would stop here and there for a lunch or a night, or to visit something and foremost enjoy the view looking out of the window at valleys, the sea, mountains, etc.

Which route would you suggest?

Obviously, many routes are possible, such as:

  • the classical one, using the Shinkanzen. Been there, done that in the past weeks.
  • north through Tottori and later Kyoto
  • south through the north side of Shikoku
  • south through the south side of Shikoku
  • combinations and variants of the above

PS: I've already done day trips to Tottori and Imabari, so I would skip those towns.

by snowghost1291