Requirements:
1. 4000 gold (for scrolls later on)
2. GWEN Campaign
3. Nighfall (Ofcourse)
**This trick is also able to be done by a prophecies character. What you have to do is get to a 10 and get a runner to Lions Arch and you can travel to the north!
1. Attain a level 10 in Nightfall (This is easily done as there are tons of quest to do and all are decently easy. It shouldn't take that long to get that level)
2. Travel to Kamadan (MUST BE A LEVEL 10) and obtain Hole In Istan from Bendah who is near the top of the stairs leading to the Dye Trader and Merchant.
3. Complete the quest (This should be easy because most enemies are around level 8 and you will automatically be buffed as a level 20)
4. Upon completion you will be at Boreal Station and get some experience and the Heroes Vekk (Asuran Elementalist) and Ogden Stonehealer (Dwarven Healer) and Against the Destroyer will appear in your quest log which is the main quest that the other factions quests branch from.
5. At Boreal you can take the Hero Tutorial (for all you prophecies characters or if you just want some more XP). But if not follow the Against the destroyers quest to Eye Of North and as said before, follow the storyline and you should then have 3 new quest...One for Norn,Asura, and Vangaurd.
6. The quest that will take you to the leveling spot is called Northern Allies. Follow that quest to Gunaar Hold (there will be a few enemies along the way but nothing that should worry you. The nornbear is easy enough to kill just be careful of him because he hits hard!)
7. Upon Reaching Gunaar Hold talk to Kilroy Stonekin and recieve the quest Punch the Clown, which is a solo mission (only you can be in your party) but its a brawling match and completing the quest is easy.
8. After beating that quest your are now able to recieve the quest Kilroy Stonekins Punch-out Extravagenza! This is the quest that will solve all of your leveling issues. But again this is a solo brawl quest (remmeber to be alone in your party and to equip your brass knuckles).
9. Before starting the quest talk to the merchant at the hold and buy 4000 gold worth of scrolls of Hunters Insight. it should be around 13 scrolls whihc will be enough to level you up.
10. Start the quest and as soon as you arrive in the dungeon activate your scroll and then start killing enemies like crazy. You obtain 200 health per kill so dying isnt a problem. You should get around 450xp each kill leveling you up extremely fast.
11. After the boss battle at the end and the completion of the dungeon you can either wait for 2 1/2 minutes to get all your mised loot or map travel back to the hold and turn in your quest for an easy 2.5k xp. THIS IS A REPEATABLE QUEST EITHER ZONE OUT AND THEN BACK IN OR SWITCH TO A DIFFERENT DISCTRICT.
That is all and if done right you should be leveled to a 20 within a few hours.
Credits:
Finalhack13 (My IGN is Sacred Holy, if you have any questions)
GuildWiki (Official) for quest information
TanK,Steboy93,and MarxF for providing info on leveling

Also if you have any comments, questions or issues post on thread