Suggested day trip from either Tokyo, Kyoto or Hiroshima

Hello,

We're fortunate that we have an extra day on the last leg of our trip, which is from Kyoto to Hiroshima/Miyajima for one night and then back to Tokyo for our flight home.

We had initially planned to spend four days/nights in Tokyo with three full days and a day trip to Kamakura.

However, now with our planning we have an extra day. So should we:
1. Spend 5 days in Tokyo?
2. Spend one day in Osaka instead on the way back from Hiroshima to Tokyo?
3. Explore a possible day trip from either Kyoto (we're already going to Nara), Hiroshima (we're going to Miyajima) or Tokyo (we're going to Kamakura)

Any suggestions please? We have the rail pass so travelling will not be a problem.

Thank you.

PS - The possibility of Nikko did come up, but since it's 2 hours in each direction I think it's a bit much if we're not spending the night.

Thanks.