The Norway map is Terra which means it has a "New World" with City States, resources, and huts that is first come - first served, which is great for Norway with their seafaring ability. You should be able to get over and control those city states long before the AIs manage, even with just one city - just make sure you settle on the coast or you won't be able to make Longships until you get a Harbor! Not sure what high seas means, maybe just more water and less land?