If you intend to come and spend a winter season in Niseko, you will have to survive in Japan for a few months, if not more.
Niseko is a very special place in that (at least during winter) you can go into most of the shops and be understood if you speak English and not a word of Japanese, but drive 20 min in either direction and no one will understand you.
Besides, if (as we strongly recommend you) you intend to visit Japan before and/or after your winter in Niseko, a bit of local language does help.
To be honest, there are as many books about "Learning Kanjis easily" than there are about "Losing 10 kilos in a week without effort". For the same expected results.
Reading Japanese will not come without a serious dose of work (It takes 10 years for kids to learn them all, and they mainly learn this at school) - but speaking basic Japanese is fortunately much easier.
For those who would like to begin studying Japanese, or the basics, here are a few tips: - First, try to get familiar with the "hiragana" and "katakana". You don't necessarily need to read and write, but just understand the principle. This will help you decipher (and hopefully remember) complicated words like "kokkaigijidomae". (Think about the tip whereby it is easier to remember 3 distinct 3-digit numbers rather than a single 9 digit number). - Then, I would read this: http://www.dummies.com/how-to/content/forming-sentences-in-japanese.html. Japanese has a very logical way to work and to build sentences, until an intermediate level at least. If you have a logical mind and you understand the principle, you will be building complicated sentences in no time. (Just need to get vocabulary then). - Subscribe to podcasts to get familiar with the pronunciation. http://www.fluentu.com/japanese/blog/learn-japanese-language-podcasts/ I recommend the "fluentu" app (Android/iOS) which is pretty well done. They basically dissect real Japanese videos, sort the videos by Japanese level, and present you: required grammar, required words, etc... So a great way to get exposure to the language from far away!
Good luck learning Japanese!