Nia:
I spent 3 months backpacking (hosteling) in China last year. If it’s natural scenery you’re after, you’ll have a better experience in the southwest quadrant of the country — Guangxi and Yunnan provinces are famous for their scenic beauty. If it’s rugged beauty you are after, then the high plateaus of Qinghai/Tibet — or the desert of the northwest are well worth a visit.
Backpacking trails as we know it are pretty nonexistent over there. To the extent there are trails, I think they either lead to historically sacred Taoist / Buddhist peaks (don’t expect true wilderness there) — or are in far away places that connect remote villages — utilitarian trails and roads — not trails cut for scenic purpose.
Googling around, I found a site that might be of interest to you (don’t know anything about them though).
As above, China is intense — intensely crowded and sometimes chaotic. But robbery and violent crimes are rare. Foreigners are a dime a dozen in Shanghai — but once you venture out into the countryside, YOU will be the star attraction. Expect friendly — but nonstop staring from people — and keep up your humor.
Traffic woes aside, you will likely be much safer there than here.