I know exactly what you mean when you describe the “new/old” thing, that is exactly what Kuanzhai and Qingtai Lu are.
One place that comes to mind though is Xiaojiahe which is to the west of Yulin. It’s not Ming-dynasty old but it’s really old and has character.
One more thing, I know exactly which alley you’re talking about opposite Age of Red! A bunch of people call that place Funk Street. It’s been renovated recently and has changed a lot, but as you know it used to be this real crazy alley tucked between an area that has changed a lot in previous years. That one alley managed to stay unchanged for a long, long time.