Gulp ... I haven't stayed there but that hotel is located in a very inconvenient spot. Looks like a location for a "resort" rather than a city hotel. I would definitely choose a different hotel.

I also agree with abmj-jr that 14 days is too long for tourism in Hiroshima. For a first time visitor, I'd probably suggest spending 2-3 nights in Hiroshima at most. In that time you can see the peace park, museums, Miyajima, and a few other things (downtown / cathedral etc.).

But for that kind of trip, I think you can find a better location than the Grand Prince.