Big cities are challenging. I don't wanna be pessimistic and call it hopeless. It's still doable. But I wouldn't wanna live in a big city. I would strategically relocate. Also, you don't HAVE to be in a rural area. Suburbs are totally feasible to bring change and win local elections.
But trust me, it doesn't take much smarts to get on the Town Council. Just be friendly and have patience and perseverance. Once you have a majority of liberty lovers on the Town Council...bring some real change!
You do need to be very smart to handle all the jury stuff. That is challenging. But like you said, it's more effective than educating hundreds of millions of fools.