Mt Koya to Tokyo

Mt Koya to Tokyo, where to stop and stay over for a night.
Hey all,
We are in Japan early September staying in Tokyo, Kyoto and Mt Koya then heading back to Tokyo. We would like to make a stop along the way for one night. We have our baby with us so not looking to climb Mt Fuji or a bustling night life :) We are thinking to go by train, but nothing is planed yet...any advice would be much appreciated.
Thanks
Kind regards
Lisbeth

I would explore Osaka a bit if I were you, then get a Shinkansen to Tokyo next day.

Thank you for your answer. We would like to get out of the city, do you think Hankone is to far away for one night.

Yes, Hakone is too long of a way off Koyasan (trip will take around 6 hours) to actually enjoy it properly. Something in the Kansai area is better.

Actually, I don't know how many nights you are staying in Kyoto but you can also split your Kyoto leg in two. Get to Kyoto, go Koyasan, come back the following day to Kyoto and then off to Tokyo when you're finished in Kyoto.