Travel northwest from Sardelac Sanitarium or west along the wall from Ascalon City; head for the Breach. Once there, head down into the tar areas and then start heading northeast. Piken Square is at the northeastern point. If the quest Barradin's Advance is active, an NPC will appear and call out to the players as they head down into the tar areas. He can guide the players to Piken Square along a back route to avoid some Charr mobs. This makes it a very popular scam run. Many senior players will overcharge newer players, only for them to find that it is a short run.