Lessons about the swamp:
1. NEVER take a boat anywhere near a swamp for much time--those Draugr archers will happily walk underwater to that boat and shoot it. Find a forest or meadow nearby to drop your ship.
2. Learn how to fight the Abominations. The hop onto a crypt method is ideal. They always show at the worst times. Use an axe or knife on em, or use fire arrows at distance.
3. Always be rested.
4. Blunt damage and a parry shield are your friends.
5. Good food and poison potions are also a must.

I play solo (on a server, so no cheating), and have been plenty safe with just iron armor and weaps in the swamp. Once you get silver, build Frostner. It's a great swamp weapon. :)