Area to stay in Osaka for several day trips

We are traveling to Japan in October. Will stay in Osaka for 5 days making day trips to Kobe, Nara and, maybe another city close by. Then on to Hiroshima. What is the best area in Osaka to stay so we are close to the train station(s) that will get us to these destinations?

My preference is Osaka Station for its convenience. There are direct train connections from there to almost anywhere in the Kansai Region (including anywhere in the city of Osaka). I prefer to stay at the Granvia Osaka Hotel inside the station complex for ultimate convenience.

Almost anywhere. Osaka has a great train and subway network.

Tennoji, Umeda, Namba or Shin-Osaka are the common ones that offer quick access to other outlying locations.

But you can save a few dollars by picking locations away from these but still serviced by subway lines.