My family and I were in China for a year about 5 years ago. We never had time for actual backpacking but we were in charge of about 20 students who were interested in Backpacking, rock climbing, etc. Backpacking and camping are sort of boutique activities in China. Gear is relatively expensive, and there is plenty of fake Goretex. Everything must be bargained very hard. I would offer one fifth of a listed price and be prepared to walk away.Assume most batteries are fakes. In short, bring equipment you trust. You'll be able to get fuel like canisters, but little else . There are down jackets and tents , but nothing of very high quality. 5 years ago many people were traveling to music festivals and tenting there. People who were more serious about actually backpacking went to places like Leaping Tiger Gorge. You will find that China is very crowded and much of what you would think to be wild is actually cultivated land -all the way up to mountain tops.Many mountains have tramcars and steps going way up. Safety is usually much less of an issue in China. People may cheat you or steal your purse, but in general you will feel safe most of the time. In train stations people often wear their backpacks backwards facing forward to prevent thieves from slicing them open with a razor. Unless your Mandarin is ok, you will have some trouble negotiating in China, but the Expat community is large and you will find many people who will be happy to go on trips with you etc. Watch out for Chinese students who will want to practice their English with you endlessly. China is vast. Trains are great. The South has bamboo and Eucalyptus forests and Karst mountains. The North can be very cold and the desert is brutal. Shanghai and Nanjing are Temperate and hot and humid in Summer. We intended to go to a park in the far West of China which was referred to as "China's Yellowstone" but never made it. I suggest you subscribe to The Oriental list run by Peter Neville-Hadley and read his books on Beijing and The Silk Routes. I'll be happy to answer any questions if I can. Hiking the great Wall can be fun-many camp overnight in their Watchtowers illegally.
China is intense. My motto was " A kick in the head every 15 minutes". Whatever you do , don't let your employers use you by housing you in some suburb or working you 6 days a week. Investigate wages and rent. They will try to use you like crazy until you know better.2 years is a long time in China. It will seem like 4 in normal life. Good luck.