Is there any way to place a helmsman NPC at the wheel of a ship? I got the message that there were characters in inaccessible locations and the module couldn't save. Trying to get around it by placing area transitions at the top and bottom of the ladder just got me the message that an area transition was inaccessible as well. So, is the entire bridge treated like a wall, and is there any way around that?

Well, there's no walkmesh on the bridge of the ship, so no actual npc or pc character can go up there technically speaking.

You can, however, place objects on it, so if you were to find, or make, a placeable object of a person, you could put him behind the wheel, and of course talk and everything as well - he just wouldn't be that, eh... animated.

Great, thanks. Is there any way to see where the walkmesh is and isn't, like in Arcanum?

Not that I know of, other than the obvious place-an-npc-and-the-toolset-crashes method.

I have no idea how people edit walkmeshes for new tileset haks.

I know there is a way to place Walkmesh. Seen it done in ALFA, although I'm not 100% sure how.
I'll look into it for you.