Permits generally take seven days to process and cost from US$300 per site. You'll need to provide passports, proof of medical insurance and a clear itinerary. For popular but allegedly treacherous mountains such as Sìgūniáng (四姑娘), the association will arrange for a mandatory guide/liaison (from ¥300 per day). It can also assist with gear, meals and horses.
Call first, as there's often nobody in the office.