Disagree with the above. One day for Kyoto and a half-day for Hiroshima (forget Miyajima) is doable if very rushed.

What kind of hotel are you looking for that seems pricey?

If I were doing this, I'd find an inexpensive business hotel out by Shin-Osaka Station and stay there. It makes for an easy connection one day on the bullet train to/from Hiroshima and another to Kyoto. I'd also get a JR Kansai Area Wide Pass. The Rail Pass would cover your trip to Kyoto and your return to KIX from Kyoto at the end of the trip, your trip from KIX to Shin-Osaka upon arrival and the round-trip on the bullet train to Okayama on the way to and from Hiroshima. You would have to pay out of pocket for the round-trip from Okayama-Hiroshima-Okayama as the Wide Area Rail Pass only goes as far as Okayma.

Examples: http://www.japanhotel.net/Rates.aspx?HotelID=383

https://www.westjr.co.jp/global/en/t...s/kansai_wide/

Frankly, you might be better served to skip Hiroshima and concentrate your short stay in and around Kyoto but I assume in the above that you really want to visit Hiroshima.