The hall of echoes quests will have to wait until after you have the battle tower (it is the final area of the game, so there is no rush to get to the quests).
You may want to head to the fjords (from the path in the far south west of Broken valley) to level a bit before finishing off the battle tower (assuming you are done everything in Broken Valley and on Sentinel island). I think level 15 may be a little low for the fight at the end of the tower, or the one after that (though if you save before the 'point of no return' {there will be a warning}, you can always reload and go level if you run into problems).
Welcome to the forum.
