A city map could work just like a miniatures game. The chief differences are the size of the figures and the detail of the terrain. I can see something the size of a pencil eraser or so (sort of like the tokens for Risk, or Axis & Allies, even Monopoly pieces in a pinch) working on the scale common for city roadmaps. This is especially true if the pieces represent units of soldiers, rather than individuals or single vehicles.

Another option is to print out a map and use immobile forces. Rather than have figures, a unit is a mark on that map. Each player takes one edge of the map, or random determination of bases can be done by dropping a coin from above the map. A unit provides overwatch for another unit to be brought in. That is, you can place your first unit within X centimeters from the edge/base, then the next unit must be within X centimeters of the first unit's position. Attacks can be made by proximity and line of sight.

The commuter player(s) have to get a certain number of their tokens to work by the end of turn five, and the tourists win by keeping that from happening. This provides a fairly consistent run time for he game.

The same ruleset could be used for Bunnies Versus Farmers or Students Versus Dealers (just say 'no', kids). In BVF the bunnies have to get to their warren before the farmers trap them (like with fences, not guns, if this is to be geared towards a younger audience). SVD has school kids trying to get to class before the bell rings, while avoiding the kids who are there to sell drugs rather than attend class. It's a positive message straight out of the 'eighties.

I think a time limit for the game as a whole would just result in a truncated game, but how about a per-turn time limit? Maybe only the commuters are under time pressure?

the tourists, I mean. Plus, giving it a firm end-point (all the commuters are at work on time or their not) would make it more playable. Possibly the commuters should be able to fight back against the tourists by cramming up all of the coffee shops.

I think something where one player was a set of commuters, and one player was a set of tourists would have some potential. The tourists would have one set of movement rules and abilities (and there would be more of them than commuters), and the commuters another. The commuters all have to get home, the tourists only have to stop them, maybe (They've got nothing better to do, "interacting with the locals" is exotic for them!

I think you could, and I think that map people would be really into creating strategy around their familiar landmarks. I know DC publishes its GIS landbase for free if you have access to ESRI products; other cities must too and you could plot a map of those cities at whatever scale you need for ease of token movement. I have a vision of a strategy game "Commuters vs. Tourists" where you have to get to work in under an hour while people from Iowa either impact you directly ("Do you know how we can get back to our hotel?") or clog up the metro and intersections.