Park your boat in the adjacent biome and walk in. Drop a work bench and camp fires to prevent mobs spawning in by the boat. Build a portal next to that work bench that leads to and from your main base for quick return in case of death.

Brew up and use poison resist meads. Like frost meads they only work before you take the damage but they last 10 minutes so consume them before you enter the swamp and renew while you are there. Poison resist meads make leeches and blobs trivial since they do very little physical damage.

When you run into large spawns of dragur there is a body pile nearby that is spawning them. See if you can locate it and then use your bow to destroy it. You might want to leave a couple body piles so you can farm entrails after you get iron gear. For dragur with bows hide behind an ancient tree so they will approach you. Step and let them draw, step back so the arrow hits the tree, (or parry block with a bronze buckler to stagger them) and then wade into melee. You can kill them with a level 3 bronze mace before they can shoot again. Melee dragur block or dodge and then melee. 3 or more use the bronze atgeir.

Long thin strips of swamp rarely contain crypts and they usually only have a single abomination spawn point. The other biomes are usually nearby so leading them out where they are easier to tackle is a valid strategy. The creatures in the other biomes will attack the abomination in preference to you and vice versa. This gives you extra time to deal with their menace (and troll/abomination battles are epic). This makes the strip swamps ideal places to farm blood bags, ooze, and entrails. They are also a good place to look for your first 3 turnip seeds. Plant those turnip seeds and expand them a few times with the seed > turnip cycle and add the spice rack to your cauldron for better foods and medium healing meads.

Use the better foods to explore larger rounder swamps that will have crypts. If you can find the Vegvisir there are usually several around Bonemass. Explore the entire swamp first and mark the crypts.

When you are ready for the crypts take enough material to build a workbench, a chest, and chest just out side the crypt that goes back to your main base. When you explore the crypt and need to empty your inventory, refresh your rested buff, repair your pick, etc. go outside and put the scrap iron in the chest and portal every thing back home. If you get killed inside the crypt you can portal right back.

When you are finished with that crypt take the scarp from the chest and walk it to your boat. If you fill the boat build a chest for the rest of the scrap. When the scrap is moved portal home, portal back to the crypt, dismantle the chest, portal, and work bench and repeat for the next crypt.

When all crypts are emptied sail the scrap back to your base and start smelting If you have to make multiple trips, deconstruct your Karve with your axe and pick up the pieces. Take them back through the portal and rebuild the Karve. Load your next batch of scrap and sail home. Repeat. If you still have a lot of scrap use that first batch of smelted iron to make nails and use a long boat to bring the rest back.

Smelt and be happy.