Haven't you decided yet where you are going to Japan?
How about taking a unique train and having a unique experience.
In Wakayama city, Wakayama Prefecture unique local trains run between JR Wakayama Station and Kishi Station. By Wakayama Electric Railway, there are currently 6 kinds of trains running on the Kishigawa Line. Those trains are decorated with each concept inside. It is truly enjoyable while on the train as seeing the decorations. Whole train is designed as the theme and it is super cute.
They are not necessarily running every day so you should check their website and the time schedule if you would like to take your favorite train.
Kishigawa Line is famous for two cats working: Nitama as a stationmaster and Yontama as an manager, and its unique trains running. You can see them at the final destination of Kishi Station. There are many people who visit not only domestic but also international tourists. Kishi Station, the final destination, has an adjoining cafe and shop for Tama, cat. The station is very cute and looks like a cat face building.
*Japan Rail Pass cannot be used on this line since it is a local train by Wakayama Electric Railway. You can transfer in Wakayama JR Station to take the Kishigawa Line. You need to purchase a ticket for Kishigawa Line at JR Wakayama Station.