Actually the “as you go…” statement is perfect instead of a fix task because in several areas these specific quests are kill quests and there are simply not enough mobs.
So instead of telling you to go to place x and grind mobs for a long period of time, you just do it while traveling back and forth doing other quests.
This can be a great time safer, especially in overpopulated areas.
Also it is not true that you’re like completely lost if you pick up a guide later. In most cases you maybe lose a few quests but definitely not like half the guide.
If you know you are outleveling the guide but still want to finish it, you can simply open the guide and mark the source quest with an “x”, this way the entire quest chain will be ignored later on.
It is done really well!