To my way of thinking, how you carry your sidearm is perhaps even more important than what you carry.
This thread "Straight Forward" thread asks how to best carry on the trail, and discuss the particular challenges of doing so.
In the city a heavy belt with a holster inside the waistband is a much more viable option than when you are hiking, right? I don't see that working even if you have a belt.
If you keep your gun in your pack most of the time, but transfer it to you person when walking to water or around town, how do you handle that? Even if your hiking pants have front pockets, this would never work with light-weight nylon ones, I think.
Is a fanny pack the only solution? Any good ones that are discrete but do the job well? Other strategies?