In japan, there is unique large public bath (sento / onsen) everywhere.Now those japanese communal bath is well known to foreigners.And there are 7 rules of Japanese communal bath.
When you come to Japan , I definitely recommend traveling by bullet train "Shinkansen". Today, the Shinkansen extends the route to major Japanese cities.
If you understand the two railroad lines in Tokyo, your Tokyo trip will be comfortable.
You may be worried at first at entering convenience stores, but please actively use it. It should be very useful and surely will be very useful for your journey.