2025 Itinerary with Setouchi Trienalle

I am putting together a visit to Japan in May 2025, primarily for the Expo 2025 in Osaka and the Setouchi Trienalle. This is what it looks like so far:

Day 1: Land in Tokyo, Shinkansen to Osaka
Day 2: Osaka
Day 3: Osaka, day in Nara or Koya-san
Day 4: Osaka, day in Nara or Koya-san
Day 5: Osaka, day in Expo 2025 or USJ
Day 6: Osaka, day in Expo 2025 or USJ
Day 7: Osaka, day in Amanohashidate/Kinosaki Onsen or Tottori
Day 8: Osaka, day in Amanohashidate/Kinosaki Onsen or Tottori
Day 9: Osaka, Shinkansen to Takamatsu
Day 10: Takamatsu, day in Megijima and Ogijima, train to Uno
Day 11: Uno, day in Naoshima
Day 12: Uno, day in Teshima and/or Inujima
Day 13: Uno, day in Okayama and Kurashiki
Day 14: Uno, Shinkansen to Tokyo
Day 15: Tokyo
Day 16: Tokyo, half-day in Yokohama
Day 17: Depart from Tokyo

I'm not averse to the occasional overnight stay, but I do prefer longer stays at each given location, so as not to need to move my luggage around as much. Also, as it stands, this is one of my longer vacation plans; typically I spend just two weeks at a time in Japan, but I kept adding on places I've wanted to visit. With that in mind, I have a couple of questions:
1) Is doing day trips all the way from Osaka to Kinosaki and Tottori worthwhile? I'm going to use a regional JR West pass to cover the train fare, but I'm still looking at one-way travel times of at least two and a half hours. Also to note, I had wanted to go to Tottori in one of my past vacations, mainly for sandboarding on the dunes, but scrapped it for simplicity.
2) For the Trienalle, would it be better to spend more time in Takamatsu, or skip it and just focus on staying in Uno?

I really wouldn't stay in Uno, and I definitely wouldn't plan a sequence where I start the day in Uno, go to Okayama and Kurashiki and then go back to Uno, only to leave there the next day to travel onwards (presumably having to go back via Okayama again).

There is nothing in Uno, and the ferries and trains to/from there each day will take a chunk out of your day.

I'd either stay in Naoshima for two nights, and then Okayama for the night when you want to visit Okayama, or I'd swap (one or both nights in) Naoshima for Takamatsu. Ferries to the islands may be a little longer than from Uno (I don't know - you'd have to check), but Takamatsu is a much better place to come home to at the end of the day, and is a destination in its own right (as well as having great udon).

There are cheaper places to stay than Benesse. However, if you have a love of contemporary art and the inclination and ability to splurge for a night then Benesse is fantastic and supremely memorable.

Thank you for your suggestions, Winter Visitor. I did think about choosing Naoshima as my home base at some point, but the lodging situation didn't look too promising. It's not like there aren't a lot of choices on the island, but admittedly I was focusing on the area around Miyanoura Port, for convenience's sake. In contrast, I had my heart set on a particular lodging in Uno, Guest House Uoi (https://guesthouse-uoi.jp/en/). That said, you do have a point about there not being much to do in Uno itself, although I don't consider myself much of a late-night person.

As far as transportation goes, I'm a lot happier with the ferry connections from Uno (20 min. to Naoshima, 25-40 min. to Teshima) than from Takamatsu. Even doing Okayama/Kurashiki as a round-trip from there (55 min. by train) is comfortable for me. The main advantage of staying in Naoshima, as I see it, is having a direct ferry to Inujima, and even then I've worked out a possible transfer or two to get there to/from Uno.

This is my highly subjective personal view, but I'll just say that after the first time we stayed at Benesse House we twisted our itinerary quite significantly on two more trips to make sure we stayed there again.

Expensive, but IMO worth every penny and something I can call up in my mind as a sublime experience several years later.

Whatever you do, I'm sure you'll have a great time. Hope you get to try plenty of the fresh Inland Sea seafood!

Thinking about it, I suppose I could split the difference and do this:

Day 9: Osaka to Okayama/Kurashiki, overnight in Uno
Day 10: Uno to Naoshima
Day 11: Naoshima, day in Teshima and/or Inujima
Day 12: Naoshima to Takamatsu
Day 13: Takamatsu, day in Megijima and Ogijima
Day 14: Takamatsu to Tokyo

That way, I still get to experience Guest House Uoi, while spending more nights in places with more going on. I can even replace my Kinosaki Onsen day trip with Matsuyama/Dogo Onsen, from Takamatsu. Still a long travel time, but easier to plan around once I get there.

With that, I have another question. Should I try to fit Teshima and Inujima into one day (mainly their art museums), or just spend the whole day in Teshima to explore the other works around the island? Also, do you have any thoughts about the other question I asked before, about doing those longer day trips from Osaka?

Just a thought: what are you looking for in Dogo or Kinosaki onsen? If it is the historic buildings that mainly caught your attention, then ignore my following suggestion :)

From Takamatsu, going to Oboke takes about the same time as Matsuyama. There are several hotels allowing day trippers in the area (I went to hotel Kazurabashi, which has an open air bath with an awesome view). I had a car, but this part of the Iya valley it is also doable by public transportation.

Oboke - I know it's a gimmick, but I'm just saying... "take a cable car to the onsen, anyone?"

https://www.oboke-iya.jp/en/hotels.html

https://www.iyaonsen.co.jp/

https://www.iyaonsen.co.jp/spa/#section04

I thought about Iya Valley here and there, too; it looks like a lovely change of scenery. I had trouble trying to draft a possible day trip there, however, since 1) the bus schedule is a little sparse to work with, and 2) there seems to be not as much to do, at least in the easily-accessible areas. There's the onsen hotels you mentioned, the vine bridges, possibly a short boat cruise in the Oboke Gorge... what else?

As for Matsuyama, and Kinosaki Onsen for that matter, I suppose it's the historic Meiji/Taisho-era ambiance, and how much I enjoy onsens in general, that's attracted me to those places. Also helps that Matsuyama's Dogo Onsen has a connection to Spirited Away. ^_^

In case you are not aware, there is construction work being done on Dogo Onsen which is at least worth knowing before you commit:
https://dogo.jp/en/construction-report.php

Concerning Teshima vs Inujima, the Seirensho on Inujima is one of the best of the Setouchi Art sites, in my opinion. It really feels like stepping into a world in the sky. Teshima is nice, too, though.

About Tottori: If your only goal is to try sandboarding, then you could easily do that in a daytrip from Osaka. Actually, if you take the earliest train, you arrive in Tottori before 9am, so you could have a full day to see the sand dunes, sand museum, Tottori Castle, Jinpukaku, and other sites like Kannonji Temple or other museums before returning to Osaka.

I understand that the Dogo Onsen renovations will be completed at the end of 2024.

There's the onsen hotels you mentioned, the vine bridges, possibly a short boat cruise in the Oboke Gorge... what else?

There is indeed much less to do/see compared to Matsuyama or even Kinosaki, my suggestion was only for the incredible bathing experience. You could stop at Kotohira on your way back to Takamatsu to extend your day a bit.

And yes the renovations at Dogo onsen should be completed this year (the full reopening is scheduled for next month iirc).

--I thought about Iya Valley here and there, too; it looks like a lovely change of scenery. I had trouble trying --to draft a possible day trip there, however, since 1) the bus schedule is a little sparse to work with, and 2) --there seems to be not as much to do, at least in the easily-accessible areas. There's the onsen hotels --you mentioned, the vine bridges, possibly a short boat cruise in the Oboke Gorge... what else?

There's lots more to do in the Iya valley, I'm going to spend 3 nights there this October but I'll have, and to make the most of it you need a car.