Hi Dan, this is Gerald Yip from Hong Kong. When will you be traveling to Shenzhen? There isn't a lot going on in terms of orienteering events during the summer months as it's too hot here, but things tend to pick up again in September. You may find the OAHK 2016 fixture here
As far as running, there are a number of easily accessible trails all around the city, just not many runnable forests due to dense vegetation. Depending on the timing and location of your visit, I can give you some recommendations. If you have other questions, feel free to send me an email anytime.