Surprisingly, yes, there's really not a lot of McDonald's or other chain fast food restaurants downtown. You can try exploring in Google maps to get a feel for it (consider eg the area around Mercer and Dexter Ave). You can get to one, but it may be a half hour detour on foot. What is closer will be awkward as they describe.
Thanks for that. I have to agree to being surprised. I've just looked on maps from my last Sydney office, for some comparison: There's a McDonalds at 377 George St and at 600 George St, both about a four minute walk. There's a third inside the Westfield which would have its own bathrooms. KFC is three minutes away with bathrooms.
The Marble Bar is a 3m walk, Century Bar is 5m, Ryan's Bar is 9m, Burrow Bar is 5m, and Papa Gede's is 3m. All of this excludes the mass of pubs and clubs that shutdown due to lockout. I definitely feel out of place with what you've shown me!