Grammar and usage is more important than Kanji, actually. You don’t really need 2000 Kanji to read, but you must be able to read the Kana in-between.
Furthermore, 100% of kanji in N4 is around Level 27… not everyone have to go to Level 60. (And Level 60 doesn’t even cover all Joyo Kanji. Joyo = general use, but in reality, there are more general use Kanji than Joyo.)
For the test drive of reading, I recommend either Satori Reader or Japanese Graded Readers.
For Max Speed, to supplement AnimeCanuck’s said interval, I recommend one User Script: [Userscript]: WaniKani Ultimate Timeline, if you aren’t constrained by your mental capabilities, of course.