1. Join any raid using Dungeon Finder
2. Get in combat right before joining
3. Join raid, when joining it should kick you back out again and you''ll be teleported to your Hearthstone Location with an error message saying "Unable to zone in while an encounter is in progress"
I found this by accident as I was just annoying the horde at their PVP Vendor, I believe you can use this method anywhere in order to get to your hearthstone location.