MBTHVSK

Have you considered steering them in the direction of, say, simple motion based minigame or rudimentary forgiving 2D platformer in case this doesn't work out?

or 3D atmospheric non action game

hmm, maybe it reminds them of an old movie or there's some weird in joke involving the phrase "the last of us"

I agree with you, Manhattan and any majorly urbanized area is like that. Maybe try going to a beach in the outer boroughs.

Have you....ever just gotten bored? I can't imagine walking every block in Gerritsen Beach, for example, and not getting really bored. The streets aren't even that far apart.