What level, what zone.

[Bollwerk]

Go back to Hellfire and finish it out, you can make it to 62 WITH going at 58

I did every quest in Hellfire starting at 58 and didn't even make it to 61.

I am also 4 boxing so instances are a bit tougher.

There are some quests in Hellfire that you can't get until you hit 61 though. The Cenarion Outpost comes to mind.