Now I'm not attempting to revive the, amazing, HQ Cartography discussion (though it might come in handy from time to time)...
But here we have some maps. I will take at face value that the Hero Quest world is "loosely based on the Warhammer fantasy world." Hence, Warhammer maps are helpful, but don't have to be final or even definitive. They are more there to fill in gaps or help smooth inconsistencies where they come up. One map is taken from the EU quest book of Return of the Witch Lord. The other is taken from the Japanese Hero Quest's Quest book.
My purpose here is in examining the Hero Quest world as portrayed in these two maps (there is another map somebody showed once that is from one of the novels). It clearly shows that Zargon's forces (or the Dark Demon King Grimdead, as he is known in the East) had a presence in the East, where the chaos god's resurrection was attempted. Nifon Island is fantasy Japan and the UK's Hero Quest world is the "old world" of Western Europe and the British Isles, with the realm of Chaos assumed to be Scandanavia if I understand it correctly. Other factions are spread around, with hostile groups in the South (fantasy North Africa) and East (fantasy Russia). Then there are big stretches of "nothing" until we get to the fantasy Pacific islands.
So I'm wondering, how do Zargon's forces move into the eastern Islands? Where they there a long time ago, or did they travel over land (or by sea)? I had this idea that they were travelers and sailed around on Orc ships and maybe setup base there at once point.
Then again if you don't take the regionalist approach and just say "wherever evil crops up there it is" and you have various groups pledging allegiance to Chaos and then Zargon sending spies to seek out and recruit them to his cause, to unite all the "evil" factions together to conquer the world.
So how did Zargon's forces get to Nifon Island? Does it matter? Did they travel over land and then by sea, did they sail all the way over there. Did they fly on dragons? Was there a magic portal that teleported them closer? I could see them traveling through the Ogre lands (coincidentally my gaming group is playing Against the Ogre Horde at the same time as the Japanese Game System, with two different groups of Heroes).
Maybe this is over thinking what is a simple game, but I'm welcome to hear some creative or imaginative ideas. It's more background, size and scope and a way to explain why there are so many Orc pirates sailing around and what they might be up to, in an attempt to fit in certain Remake elements in a way that doesn't suck.

Warhammer super detailed map(ONLY for reference, remember, I'm not saying everything has to match Warhammer fantasy!)
Then again, maybe this world is a lot smaller than ours in terms of land mass... maybe Nifon's islands are just on the other side of the world edge mountains?
Or maybe the Alchemists of this world have figured out how to build Hot-air balloons? (possible lead in to the Heroquest "steampunk" revolution). They're not good for transporting much other than people, though.