Water or land, either would work for supplies - fellow ships, shipwrecks, or natives.
The landing points aren't just where the fellows stopped for a quick washroom break, except perhaps Disko Island. King William Island is where remnants of the Franklin expedition were found, including the famous (and only) note. It's as far as the ships made it, and where the men set out on foot from. Amundsen spent two years there at Gjoa Haven with the natives, so named for his boat. Devon Island (Beechey, actually) is where the mummies from Franklin's crew were discovered. McClure, though I didn't show it, actually sledged across Banks Island (while camped there for winter) to the north coast, where he saw Melville Island, earlier landed by Parry, and then knew the Northwest Passage existed.
Penalize all water? Maybe dead ends - basically any water without a path on it. I could ring those ones in dark blue, to say "this is water, and you'll be losing men here." Logically, Hudson Strait/Bay would be losing territories too, but perhaps Hudson gets points for trying.
This may drive people to try to capture and travel only along the routes, and completely avoid Ellesmere Island and the whole Northwest section there.
If water territories lost men each turn, then wouldn't they have to all start neutral as well? Or at least be evenly distributed by starting positions.
and where exactly is it confusing in the middle? Is it Cornwallis, Stefansson? Is it the water, Parry, Lancaster? I see it could be confusing where Parry meets McClintock channel, it looks like it has to pass through this Stefansson first, perhaps. Somerset can certain be more in line with its circle. Is it the fact that three routes run through the middle, the lines confusing? And we do know the lines don't make a transit route of sorts, and are merely set below their water/land territories, yes?
Current Map Project: Tokyo