Train Schedules and Itinerary Questions.

Hello!

I'm traveling to Japan in October for 23 days, and we just bought the 21 day JRP :D
I'm about to start making my hotel reservations and I'm worried about the train schedules and destinations. I would really appreciate if you could help me out with the train dates and schedules.

And if it's not too much to ask, I'd love it if I could get some feedback on my itinerary for the trip:

*We arrive in Tokyo and stay for a week, in which we'll be making day trips to: 1.- Yokohama
2.- Kamakura
3.- Hakone

*Then we'll travel to Nagoya (taking the train from Tokyo) and stay there 3 days. We'll make a daytrip to: 1.-Takayama (traveling from Nagoya).

*We'll take another train from Nagoya to Kyoto, where we will stay for 5 days, making daytrips to: 1. -Kanazawa
2.- Nara

*Taking yet another train from Kyoto to Osaka. We'll stay 2 days in Osaka.

*We want to travel to Naoshima Island from Osaka and stay the night there, then travel from Naoshima Island to Hiroshima and stay another night there.

*Finally, we'll take a train from Hiroshima back to Tokyo. We'll still have a few days in Tokyo so we're thinking on taking a daytrip to Nikko

How does it look? We've checked distances and the amount of time it takes to get from one place to another and it all looks fine, the longest train ride we'll take will be from Hiroshima to Tokyo. But we would love your advice :)

We just really need to check the train schedules and dates :)
Thank you! Best regards!