A couple of mysteries in Black and White sprung to my mind last night.
Firstly, where does the freeway run? We see it in two places. It crosses Skyarrow Bridge, curving off to the north at both ends. We also see it crossing Route 4. Additionally, we see a tunnel entrance in Driftveil City.
A plausible route thus seems to be Driftveil City - undersea tunnel - across route 4 - south down the eastern edge of the desert and past Castelia - across Skyarrow Bridge - then where? We don't see it anywhere in eastern Unova. It seems implausible that it would stop in the middle of nowhere, although if it's mainly used for transport relating to agriculture it might I guess.
Secondly, why doesn't the Subway stop anywhere but Nimbasa and Anville? There's a subway map in game, we see where the lines run. Many of the lines run outside the main Unova map, but they could still feasibly stop at cities in the game. Why don't they? There's no evidence for it just being the player who's not allowed to, you'd expect a reason given if that was the case. Are the stations not built? There is a sign saying "under construction" at Nimbasa station, but I've no idea what it refers to. Or were stations built, but subsequently closed down for some reason?