Himeji on way to or from Miyajima?

There are two options for us to do this (2 day more busy portion of our iteneary). Any recommendations for which is better?

April 5: check out early from Kyoto and take the first train out, --
OPTION A: go directly to Hiroshima, see briefly Hiroshima before lunch, after lunch head to Miyajima and explore there in the afternoon, overnight Miyajima
OPTION B: go to Himeji castle first, then Hiroshima in the afternoon and explore and get to Miyajima in the evening only, overnight Miyajima

April 6:
OPTION A: leave Miyajima fairly early and go to Himeji Castle, then out around 16:00 to Kanazawa for overnight there
OPTION B: Miyajima sightseeing in the morning, then in the afternoon go to Kanazawa for overnight there

Basically: Himeji castle on the way from Kyoto to Hiroshima/Miyajima, or vice versa and Himeji castle on the way from Hiroshima/Miyajima to Kanazawa

Train schedule wises it works out both ways. I am leaning more towards option A. Just hopefully either way enough time (2/3s of a day at best combined in Hiroshima and Miyajima).

Both options look good to me. I don't think it matters which one you choose, as long as you keep the castle's opening hours in mind:
http://www.japan-guide.com/e/e3501.html

I've traveled from Kyoto to Miyajima via Hiroshima in one day.
Mind you that you'll easily stay in Hiroshima for quite some time if you plan to see the sights (which you should). It's a lot to see and I wouldn't rush it.
I guess we were done there around 5-6 PM before we headed to Miyajima and our inn.
Miyajima is a wonderful place to stay over night and explore after all the tourists have left. But it's also a wonderful place during the day, so I would consider spending a great deal of the day there as well before you move on.