Problems with Japanese Itinerary
 

This Oct/Nov I've made reservations to stay in Kyoto for 11 days. My original plan was then to travel to Kurokawa Onsen for 4 nights and 2 nights in Fukuoka (sumo matches)and then back to Kansai and home. Now I am thinking of taking two days out of the Kyoto stay in order to go to Naoshima. Is this something I shouldn't miss? Would it be better to skip Kurokawa and see Naoshima instead? Or am I playing around with apples and oranges? Please help!

In March we went to Hakone, Koyasan, Kyoto, then Okayama to Naoshima, Miyajima & then Fukuoka to get a hire car & Kurokawa for 2 nights.
Naoshima is wonderful and although we stayed one night we really only had less than a day to see things as we had to jump up early next morning to get to Miyajima. 2 days would be good for here. The art works are in "small places" - so people are only allowed in in small numbers, so it takes time to move around, but is very worthwhile.
We stayed at The Oval, Bennesse, which was wonderful.
To get to Kurokawa is possible on public transport, but you would need to plan carefully as its limited (for this reason we got a hire car, although we still had our JR pass). Kurokawa is a place people go to use the onsen & we really enjoyed it & had our own private bath in the room. We stayed 2 nights. I think most people only stay in a place 1 night & then move on to try other things (am sure KimJapan will be able to comment on this) - we had on our breakfast table a sign saying "continuing guests" - everyone else was new on day 2! I think 4 days at Kurokawa is too much, 2 nights is fine & perhaps sample 2 ryokan depending on the amount of luggage you have etc.
Just one thing - for Naoshima, many museums actually are closed on the Monday, so if you do decide to go there (& it is lovely), take this into account.

Do you have plans for your days Kurokawa Onsen? Are you hiking up Aso-san or something? Four nights is probably two nights too long.

Kumamoto or Beppu would be a good stop on the way back to Fukuoka.

Thanks for the advice. I think I shall go to Naoshima for two nights, cutting two nights out of Kurokawa. So revised plan is to train/bus/ferry it to Naoshima, continue on to Fukuoka where we'll rent a car for the two nights in Kurokawa, then back to Fukuoka for the last two nights. Sounds good and thanks again.

You could keep it to one night in Kurokawa Onsen. Check in to your ryokan at 3PM or whenever they say and leave late the next morning.

From Kurokawa it is also easy to drive to Takachiho
http://hometown.infocreate.co.jp/en/.../takach-e.html
this was beautiful & also they have a very interesting "play " that is performed there, unfortunately this is later in the evening - so unless you are staying here (we had to drive back to Kurokawa) difficult to see.
Just one more thought - to go from Naoshima to Takamatsu by ferry is also possible. We didn't do this, but I considered it as crossing the Seto Bridge (quite a few postings here on this) sounded so interesting.