This seems really simple no? Like just look at the subway map?
I had to use google just to find Claremont Parkway on the map :) (I did find 13 av. I imagine people who this is their first time in NY would probably also be confused with 13 st)
And from the article it seems like the navigation inside the subways were also very hard - they are not intuitive even now (with some entrances only allowing one way for example, and you have to go out and back in again)
"In Upper Manhattan, downtown 1 skips 137 St-City College, 125 St, 116 St-Columbia University, Cathedral Pkwy (110 St) and 103 St
Aug 1 - 4, Fri 9:45 PM to Mon 5:00 AM
For service from these stations, take the 1 to 168 St and transfer to a downtown 1." [1]
There are often many simultaneous service changes.
1. While the new subway map (introduced only a few months ago!) makes it pretty easy to tell what stops where, the old subway map didn't. It was easy to see which stops were marked as "express" (white) or "local" (black), but which trains are express and which trains are local? That's the trick, isn't it?
If you looked closely you could see the little letters telling you exactly which trains stopped where... but I think I lived in New York for years before I noticed those! Even with the new map, which does an admirable job at clarity, there are pitfalls for the unwary (someone unfamiliar, for instance, might not think too much of that circle around Gates Avenue), and they were much worse with the old map.
(Also, the yellow and orange trains are just plain confusing; the subway map will give you the correct information, sure, but you have to make sure you don't accidentally misread it, and those lines are easier to misread than most. And don't get Queensboro Plaza mixed up with Queens Plaza! If you didn't know they were different, you might think they were just long and short forms of the same station name... they're not!)
You're right that correctly reading the subway map does entirely negate this first point; but the point is that reading the subway map is surprisingly easy to mess up, and was much easier to mess up just last year.
2. "Just look at the subway map" tells you which train to take. It does not, however, tell you how to navigate the station or identify your train. I live here, I know how to read the signage, but tell a tourist to transfer from the 4 to the 3 at Fulton Street and they're likely going to have some trouble, turning around a bunch and looking for another way before they finally hit upon the correct approach. And once you're at the right platform, there may be two tracks. If you don't understand the signage, you might pick the wrong track; even if you are making sure you get on a train with the right letter, you could get on a train going the wrong way.
3. Let's say you mess up and get on a train going the wrong way. Where can you turn around? Remember, the game requires you stay within the subway system! Many stations in New York City have separate entrances for the two directions with no in-system way to switch between them (and no if you break the rules of the game and go outside, it isn't a free transfer, either). This isn't indicated on the map at all, nor will it necessarily be immediately apparent once the train stops there.
4. Finally, the subway map gives you an accurate picture of how the subway normally work... but this is New York and there could be reroutes. There will generally be some way to know about these before you actually find yourself going down the wrong path, but, if you don't know to look/listen for these, you may miss them. The map ain't the territory, you know. :P
I do think that Samson overstates the difficulty (at least currently; he was writing in 1980, it may have been more accurate then!), on the whole I agree that it's not actually hard... but it's still harder than "just look at the subway map" would suggest, due the ease of misreading said map, confusing within-station navigation, and the occasional necessity of off-map info.
(Now, if you want to introduce some real difficulty into the subway game, try playing it as a person with mobility issues...)