You have to go far southwest around the mountains, almost to Kragenmoor, and then back track south east along the bottom of Stonefalls crossing a bridge over lava. The gate way to Deshaan is before you hit the dark anchor. From there just keep going east by south east. Mournhold sits near a range that bisects Deshaan, so you can't really miss it. But there will be many enemies in the way.