is it possible?

Hi there!

Whoa that's a lot of travel! Technically is possible but you'd spend a lot of time traveling and there may not be left for sightseeing. Personally I'd leave Hiroshima out and stay a day more in Kyoto or Osaka, this would take a lot of your travel time away and make for a more relaxed experience around the Kansai area. I'd use a 7 day JR Pass use it to cover most of your long distance travel, for instance from day 4-10.

Have a great trip!
Daniel

then, is there any night bus or night train from yamanaochi to osaka or kyoto?so that i can save time travel.

I am not aware of a night bus service between yamanaochi and Osaka but there are multiple buses between Nagano and Kyoto/Osaka.

sorry to bother you again..just kind of become more n more confuse looking at the train route.
just want to confirm..if we buy suica card+nex return ticket, we can use it to hitachi seaside and kamogawa seaworld right. because we thought we would like to buy the 7 day jr pass and start using it on 5-11/4 n buy that suica n nex return ticket n use it on 4/4 and at the end from 12-14/4..

Yes you can use the Suica card for the Hitachi Seaside and Kamogawa Seaworld. Using your Suica card basically is like buying normal tickets but instead you just swipe your card of the gate when entering and exiting the station.