Creating a multi city directory site

Hi Team

I'm building couple of multi city directory websites. These websites have below content
1. Directory Listing of the respective city for a genre - POST TYPE 1
2. Related events for the city - POST TYPE 2
3. local general content - POST TYPE 3
4. Global content - POST TYPE 3

I've 2 options
A. create a multisite
B. create single site with smart city selector

approach A is simple, but difficult to convert into an app. Also handling of global content is always a challenge. I'm using apppresser for mobile app, so I'll have to create city wise mobile app, which I'm not willing to.

For approach B, I'm looking for a smart city selector. Once a city is selected, then only local content + global content should be displayed. Creating city as taxonomy doesn't help as I've multiple post types. If a city is selected, it should be added for all the loops of the website.

Any pointers pls.