The only ryokan we've stayed in was in Kotohira. (Where I climbed 800 steps in the rain to a temple) The rest of the stay has been more or less western style hotels. We only went over the island for the afternoon from our hotel in downtown Hiroshima.
(Our tour guide mentioned the aquarium, but we probably wouldn't have had time, and she also said the one in Osaka is better) (though we probably won't have time for that either)
All our check in have been fairly straightforward, because we're on an organized tour and our guide has just given each of us the room keys after getting them from reception en masse
As I've said before, the big difference between my previous visits to Japan 2 decades ago is having a device in my hand that can read signs and direct us when using public transit.
(Tho also, 20 years ago I probably only spent one night in a place that didn't have a significant foreign presence)
