Sorry to hear that. Are you just going to retire?

With that big a chunk of time, maybe you could consider adding in some social/physical activities and experiences, in addition to Hilton stays and tourism. Attending baseball game is a good idea although, if you’re more into football, you might instead try a J-League game (I get bored watching baseball live, and enjoyed J-League match a lot more than the one Fighters baseball game I went to). If you go to Shikoku, Kochi is famous for watersports . How about island hopping via bicycle from Onomichi to Shikoku? Tons of great hikes everywhere. Visit a uni campus like Todai or Waseda and eat in their cafeteria. Cooking workshops…

I don’t know if you’ve done any onsens before. If not, how about starting now? Kusatsu would be a great introduction. But my favorite ones are up in the central/northern Alps near Kamikochi/Hirayu area.