The Redridge Mountains
Just to the east of Stormwind lies a region known as the Redridge Mountains, with a quaint fishing village known as Lakeshire at its center. This is a fantastic spot for questing around 17th-24th level, and believe me the local NPCs have an ample supply. It is also an excellent place to upgrade your tradeskills to the journeyman level if you haven’t already taken the time to do so.
When you first enter the area, there will be perhaps a dozen or so NPCs offering quests, so be sure to clear out your old quests first. My first piece of advice is to travel to each and every one of these NPCs and accept as many quests as you can. This is a practice in efficiency, because many quests require you to venture into the same regions and/or kill the same enemies.
There are perhaps three zones that I have quested thoroughly so far. The first is south of the lake, which is a region filled with gnolls and dragon whelps, all averaging about 16th or 17th level. The gnolls aren’t generally very difficult, unless of course you happen to aggro too many at once. Be careful with the dragon whelps, though, as their fire breath attacks can deal out a considerable amount of damage. Take them down fast before they can do so to you.
The second region was the lake itself, which is filled to the brim with 18th level murlocs. There is a relatively easy quest where you have to find some sunken tools. Naturally, you’ll have to kill some murlocs to accomplish this, but you’ll find the tools in a chest near a sunken boat beyond the bridge and to the left.
The last region I’ve explored was immediately north of Lakeshire. You should be very careful heading up the path, because the orcs in this area are staged to ambush you at several points. Avoiding them becomes predictable after awhile, but don’t let down your guard. This area is filled with orcs, gnolls, dragon whelps, spiders, dire condors, and goretusks, oh my. Most of the creatures here are a decent one-on-one challenge at 20th level, so it’s best to save these quests until you’re ready for them.
As I mentioned previously, the best levelling strategy is to pick up all the quests you can so that you are simultaneously completing as many as possible. Every single monster in the area helps to complete one quest or another. One monster, the 24th level goretusk named Bellygrub, is a quest unto himself that wanders just southwest of Lakeshire waiting to be killed. The whole area is ripe with simple challenges that, if pursued correctly, could propel a character several levels in a matter of hours, making it well worth the effort.