China is a really cool place and Yangzhou is nice. In the cities, parts of of China are super modern (for them) but the reality is that even in cities, it feels like 1970 or 1980's in US. That means that some of the buildings use old styles of construction or accomodation.
Gyms are hard to find. You wont find any olympic lifting gyms because those are out in the countryside. Dont hold your breath for machines, get used to free weights, esp adjustable DBs and not a lot of weights.
As far as drugs (of any kind) China is very strict on their own people. They see pot as on par with cocaine and there are harsh punishments if youre dealing in that. They are much more lenient on foreigners and you can go on your business as long as youre not selling, peddling, or anything like that.
As far as AAS, I think the grand majority dont know what it is so it may be on a lower level, but again, its more lenient for foreigners. Their sports teams use it and tons of it is produced there, so its not terribly cracked down on. It might be hard finding someone there selling it, you might want to ask a sponsor for more info. Dont carry that shit through customs tho.
I loved China, but the gym situation was a real pain in the ass.
Edit: I dont know about pharmacies outside Beijing, but those might be worth a look. The word for steroid is 'leiguchun' (pronounced lay-goo-choowin'). The words themselves mean 'category','strength', and 'wine'.