To get to the Divinity Coast explorable area, leave from the Temple of the Ages and travel to the Secret River Passage in Talmark Wilderness. Once there, find and speak to Livia, who explains that you must obtain a gate key by defeating Cairn the Berserker in Loamhurst. Leave the lab area and take the road to the west and north (following the main mission path) to reach Loamhurst, fighting through the legions of Peacekeepers on the way.