I kill most things with a bow. When melee risks getting poisoned, better to kill with ranged. Draugr are really slow moving (until they see you), kind of a blessing for the bow. Can kill leeches with impunity from land that way. But in the swamp, you're always wet, so always in a bit of a weakened state. That's worse at night when both cold and wet, so I avoid the swamp at night.

I don't think 80 hours is that much. The elder is 2nd biome, so that's average 40 hours per biome. At that rate, you'll finish the plains (5th biome) at the 200 hour mark. That's way ahead of me! You might try just doing relaxing things for awhile. I hit a wall with Moder and took a break. I went exploring and sailing, and came back to it later.

The plains biome felt like the biggest difficulty jump for me. Critters are very tough there. I was averaging at least one death per day at first. It's a pretty place, looks very pleasant and tranquil. It is ironically just the opposite. If you are having trouble with the swamp, I fear your reaction to the plains... :)