User blog comment:TUSF/Light Novel Chronology/@comment-1173941-20121227131055/@comment-4631119-20121228032609

During the story between Sachi and Kirito, there are three floors as frontline: Floor 28, Floor 30 and Floor 49. Here's the details:


 * Floor 28 is when Kirito joins Black Cats of the Full Moon.
 * Floor 30 is when the whole guild dies in a trap in Floor 27's dungeon.
 * Floor 49 is when Kirito trying to get the revival item by challenging the Boss Mob.

For the timeline, here they are:
 * Floor 28: aorund April 2023
 * Floor 30: around June 2023 (if I'm not mistaken)
 * Floor 49: around December 2023