If you plan to head out own your own (without a guide), here Amiwa has a few extra words of advice to help you prepare.

If you are planning to do some camping, you should be aware that, as a rule, this is prohibited in China, though it is occasionally tolerated in some areas. It is up to you to be discrete and respectful and to use your own common sense. Obviously, your decision to go camping and your conduct while on the trails in no way whatsoever involves Amiwa or incurs Amiwa’s liability: you do some completely at your own risk.

Remember that, in China, there is no specific emergency number for searching for individuals lost in the mountains (as there is in the Alps in Europe after an avalanche, for example, to search for missing skiers). You cannot count on a helicopter to come to your aid. You alone are responsible for your own safety in remote and potentially dangerous environments. When possible, alert your friends and family, or someone you know in the area, of your plans to go trekking, and provide them with your approximate locations and schedule. If you will be heading into the CangShan mountain range, for instance, let the manager of the Higherland Inn know.

In addition to the list provided on the page "In Your Bag", here are a few more tips (not exhaustive) of extra equipment you may wish to bring with you:
Consider taking a high-quality tent and make sure you try it out in advance.
If you want to take a camping stove with you, you should be aware that you can find fuel refills in KunMing, but it is not easy to do so elsewhere (in Dali, for instance, refilling is not always possible). Gas stoves are easier to use and less pollutant, but those using liquid fuel, like MSR stoves, will give you greater flexibility in remote areas.

It may be wise to carry a mobile phone. SIM cards are inexpensive in Yunnan (a couple euros)  and will enable you to reach the various emergency numbers (American Consulate in ChengDu 13708001422, British Mission 13901014396) if you need them.  Make certain you know the emergency numbers for your country of citizenship before you head off.

Don’t forget a first-aid kit! In addition, you may want to look into some Chinese medications (mostly plant-based) and learn more about TCM, Traditional Chinese Medicine (marvellous, really!).

As far as food goes, most processed foods (muesli bars, mineral supplements, etc.) are not easy to find outside KunMing. However, you can easily get your hands on seeds and nuts (jian’guo, 坚果), peanuts (huasheng, 花生), or dried fruits (gan’guo, 干果). In Dali, for example, you can find them at the covered market (on BoAi Lu) or in the supermarket on FuXing Lu.

You may also want to take a few, oft-forgot extras: a strong, thick string (3 metres long) that you can use, among other things, to hang your laundry; a strong, plastic bag (30 litre volume) for transporting various things, including water (handy for washing clothes away from the river); or Marseille or Aleppo soap, with which you can wash anything and everything and which is much less toxic for the environment than the alternatives.

If you plan to trek in the Three Rivers area, anti-leech gaiters may be a wise investment! They are called bang tui in Mandarin (绑腿). Learn how to put them onto your legs properly (there is a special folding technique; simply pulling them on is pointless and, worse, will hide from view the leeches that do get in!).