How to get to Dreadspire Keep
If you've never been to Dreadspire Keep before - getting here can be extremely confusing. First thing you'll want to do is take the Guild Hall to Undershore or find a Druid/Wizard to port you there. If you can't get there by fast traveling, you'll need to hoof it and take the long route through Nektulos Forest. More information about how to reach Undershore.
In Undershore you will want to travel northeast to Stoneroot Falls, shown on my map above. Once you're in Stoneroot Falls the next zone you need to go to is The Hive - follow the route I take in the screen shot below to reach The Hive.
Once you're in The Hive, things start getting a bit more tricky. What you'll need to do is use Levitate and run up the large tower in the central portion of the zone, shown on my map below. On your map this location should be marked "East Obelisk". At the top of this large tower you will want to scroll in and look up; then scroll back out into third person view. This will cause your Levitate spell to descend at a much slower rate.
Now follow the blue line on my map north around the mountain until you reach the bridge in my screen shot below.