What about money management? How much should I expect to bring or be spending on essentials?
Edit: Also, again probably stupid, but what would one learn in order to read common Japanese? Is it Hiragana, Katakana, or both?
I'll post later about things you should do/research for your trip. But first a quick post on language.
Definitely katakana first. What you really need to learn is how sounds work in Japanese and how the 2 alphabet systems fit with them.
Hiragana: basic alphabet of Japanese
Katakana: set of characters that look slightly different from hiragana but function identically. Used only to spell foreign origin words.
Kanji: Chinese characters used to emphasize meaning in a sentence. Without kanji readingjapanesewouldlooklikethis. A minimum knowledge of around 2000 kanji is needed for fluent use of the written language. This is why it's considered unreasonable to study without full dedication.
In truth, hiragana won't be any use either without knowing some Japanese grammar and vocab.
That said, the ability to read katakana, and a comfort with basic Japanese phonetics and sounds will go a LOONG way.
I mean that Japanese who would be too scared and nervous to help you find a "train station" will jump right in and help you find a "tore-n sute-shon". No one can help you find a taxi to get to your hotel, but just about anyone can help you "getto takushi fo- hoteru."
People say Japanese are terrible at English, and they are-- but their English knowledge of vocab can help you a long way as long as you can pronounce English on their terms.
Likewise, the biggest complaint from Chinese learning Japanese is "too much English vocab to remember!" The Japanese use a LOT of words that come from English-- it's just not written in English.
You'll have a much easier time when you see トイレ, know that it's read "toire", and can guess it means toilet. Or see ビール, read it as "bi-ru" and order yourself a beer. And when sick of a Japanese food, find a マクドナルド, and know that makudonarudo is mcdonalds.
English words are everywhere as long as you can interpret katakana. Yes there are Chinese, Russian, German, and Portuguese words written in katakana as well, but over 90% of the time you see katakana, you know it's actually some English word, and it's just a matter of taking an educated guess.
As I said, Japan can be a lot more accessible language wise to the English speaker just willing to learn katakana and get comfortable with the way sounds are pronounced and written in Japanese (not at all difficult tasks).