Either have a base in the swamp to process / create weapons / armor and then store a bunch of iron in the longboat before leaving - or use a cart to transport iron to your ship since it's super easy to use a hoe in the swamp to make paths for carts to easily traverse.

Fire Geysers can provide free warmth for a base / outpost that you can even use to cook with and if you have a bunch you can make a path for coal runs from spawns that can instantly die when they touch water.

The wet status can be annoying but that is offset with the easy terrain and using the rested buff or potions / good foods + you can build fires in crypts to get rid of the wet status and regain rested.