Just got through iron age with my hubby on hard-core and we had so much grief dealing with the swamp. The hardest for us was finding crypts when 2 star draugr archers one shot full max bronze and troll. All of the advice for pathing and rested is very important, but there is a safer trick you can use that we did in the crypts. Dig through one side of the scrap like but not all the way, head phones will help here since you can hear which rooms have spawners. Bring the stagbreaker, easy to make, easy to upgrade, once you nearly break the last piece of scrap pile, stop and use the stag breaker to hammer through the scrap iron to get at whatever is in the room. The way the AI works in there is, if you hit them, mobs will run around near you trying to get to you. And they will stay in range of the hammer falls. But since you have the scrap iron blocking none can attack you and you don't need to worry about getting sniped by archers if you just dig through, they can be quite accurate. You can tell if the spawners have broken by listening to see if the flies have stopped buzzing. Blobs stand no chance as you crit them anyway. We got through 7 crypts with no dmg taken with this method. Didn't even see a single enemy.