Thanks everyone. I'll be arriving on the redeye flight from Bangkok at 6:30 a.m. and have decided to go straight to Hiroshima that morning.

My plan is to buy the Kansai-Hiroshima area pass. I guess what I would do then is take the airport train to Shin-Osaka station and then the Shinkansen to Hiroshima?

I'm going to plan to sleep a bit on arriving at my Hiroshima hotel on the 4th, visit Hiroshima that afternoon, go to baseball game in Hiroshima the next day on the 5th, train to Osaka on the 6th, maybe another baseball game that afternoon in Osaka, all day in Kyoto on the 7th, then fly out of Osaka late afternoon on the 8th.