I think for anyone with normal memory ability, "a few days" is optimistic to learn hiragana and katakana for any sensible definition of "few" and "learn". After a few days you should be able to falteringly pick through kana text, struggling to recall some characters and probably misremembering others. As the weeks of regular practice mount up, it gradually starts to get easier. Of course, learning the kana is vastly easier than learning all those darn kanji, which is a different proposition altogethr.