For some ideas, Kind of a video guide, you can search Traveling on a Dime Japan, or just go to this link below and watch the many videos. You'd be surprised the places you can go, things you can do and see, and prices don't have to be outlandish to have a great adventure in Japan. This guy Bryan, from Traveling on a Dime, opened my eyes a bit about the awesome travel opportunities in Japan.
There is no one perfect guide, or best guide. The only real guide is experience. Japan is a very safe country, so you won't have to worry much about being taken advantage of, or robbed, or being eaten by a lion, etc. All you need is some imagination, maybe a few hints about what is possible, and let your google fingers do the walking.
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