I’ve studied it off and on since high school, but really struggle with speak. I get anxious about the times and accidentally saying something nonsensical. But we had a family show up that didn’t speak English, and I was able to do more than crank out 谢谢。
Maybe you could go to Shanghai. I heard the food is quite good there. Maybe even Singapore, though you risk everyone switching to English upon hearing slow Mandarin. Maybe you could also check out Chongqing. Basically just stick to the big cities, unless you’re mentally prepared to have to do everything in Mandarin. In any case you don’t have to commit to one city; just use the rail to visit multiple cities.
Though not in China, my personal recommendation would be to try going to Taipei. It’s a cozy city with nice people. Taiwan’s the first in Asia to recognize same-sex marriage, which is quite something. The boba tea there is also awesome. Affordable and so much better than whatever they’re selling over in the States.