Don't go into the Swamp at night until you are geared out in iron equipment. Even then, it's really not worth it unless you really need some chains from wraiths.

Make tiny Swamp portal houses up in the indestructible trees with ladders leading up (but not touching the ground...should have to jump to the ladder) or at least on top of sunken crypts. Sleep through the night and then walk through the portal to closest to where you need to adventure, gather, or explore next.

Use the hoe in the Swamp...a lot. Level out paths so you don't have to run through leech-infested waters. Make paths wherever you go. Seriously...use the hoe.

Make sure you destroy draugr spawners (body piles) on the ground if you see them. And don't try to block arrows from a 2-star draugr. Sidestep them or dodge roll until you get to them or have an archery battle using a tree to hide behind, only firing after you've tricked them to loose their arrow at the wrong side of your tree.