Scenic areas to travel around Shenzhen..

Hey everyone. I just accepted a job for an engineering firm and I will be traveling to Shenzhen, China for business for two weeks. Doing a little research I've found a lot of beautiful areas that I'd like to visit, unfortunately most of these areas are more than a days travel which is more or less impossible for me. The areas I'd wish I was able to see are stuff like the Lijing River area or Langshan mountain, basically a lot green, water, mountains, trees.. nature. I'm not very knowledgeable of the area (obviously) but I'm assuming mountains and lush forests are a lot further inland than where I am. I'll have some free days and a few days where I could travel and possibly stay overnight so basically the furthest I can go from Shenzhen is about a days worth of travelling. Can anyone recommend any areas around Shenzhen or any resources to look at for finding these areas myself? I really really just want to see some beautiful scenery and nature.

Any help is greatly appreciated and I'm pretty much looking forward to this more than I have anything else in my life.

Thanks everyone.

You are interested in mountains and waters, it means Natural Sights. So come to Guilin, it takes about 12 hours by train from Shenzhen or 1 hour by plane. Do a day tour to Longshen terraced field, a day  Li River cruise to Yangshuo, a day countryside tour in Yangshuo, then back to Shenzhen.