Good thing with swamps is that it's easy to snipe enemies from your boat before making landfall and then building on damage immune terrain be it trees or crypts.

Going in at night or being unlucky in popping an abomination are probably the worst things early on. Poison resistance shouldn't be an issue at that point and ranged draugers should be rather easy to snipe from a distance. Root armor for pierce and poison resistance and swamps become a lot easier - plains as well for that matter.