Remember, the Turbulent Timeways only has a few weeks remaining, so don't miss out!
As explained by Vexent, the key to this method is completing five Timewalking dungeons to build up the Knowledge of Timeways buff. While the dungeons themselves don't give very good experience anymore, the resulting Mastery of Timeways buff will speed up everything else.
Start by completing all 10 Delves, without turning in their quests. Prioritizing these first will make them easier, due to lower level scaling. The Delve Leveling addon may also come in handy for tracking these objectives.
Queue for 5 timewalking dungeons to build up the full Mastery of Timeways buff.
Pick up a Prey hunt in the same zone as the weekly Abundant Offerings.
Take another Prey hunt in Eversong, to be done alongside the Saltheril's Soiree event. This part can be sped up by joining groups or sharing Latent Arcana from other characters.
Turn in all of the Delve quests, while the Timeway's buff is still active, to gain several levels worth of experience all at once.
Finish off any remaining levels with more/randomized Prey hunts, Void Assaults, and/or First Craft bonuses from any crafting professions.
The total amount of experience at each point will vary based on what experience buffs you have, though War Mode, the Darkmoon Faire, and Five Warband Mentors: Midnight are all routinely available. Even if it doesn't get you quite to level 90, it should be a major jumpstart to get your new character endgame ready for Patch 12.1!
