I visited Japan for the first time March 13-28 2019, here are some general notes from the trip.
-
Trip duration: I walked a lot (sometimes 19 km/day for several days) up and down hills, to and from train stations; this was tiring enough that it was a mistake to stay for 14 days; I should not have stayed for longer than 9-10 days; this would have saved money on the JR pass (7 days instead of 14 days) and hotels.
-
https://www.jalan.net/ seemed to have the best prices and largest selection of hotels. Book at least two months early for good+inexpensive options.
-
I did not have a problem with smoke in any of my non-smoking hotel rooms in Henn na Hotel Tokyo Akasaka (100% non-smoking), Hotel IL Verde Kyoto, Hotel Intergate Hiroshima, Hotel Trend Kanazawa Ekimae, or Fudo-in in Koyasan.
-
There are a lot of smokers (sometimes in areas where it is forbidden to smoke), but their smoke was never a real problem for me.