If you want the Turbulent Timeways mount made easy...

Just get the Mastery of the Timeways buff on an alt you don't play. Then just log in every week to it. You might have to do one dungeon at most for the last 3 weeks of the event.

The buff persists through being logged out, and as I found on my druid, I already had credit on the 5 week achievement after my second run. I assume that because I already had the Mastery of the Timeways buff that either refreshing it once triggered the achievement credit, or it might have ticked up as soon as I logged in.

Either way, 0 or 1 dungeon at most over the next 3 weeks is pretty nice if all you want is that achievement and mount!