Be prepared for haze and smog which may obscure the views, but also can impart an eerie feel to the landscape. If you can, go to Guilin and take the river boat to Yangshou for some great scenerie en route. When there, there is a mountain whose name I cannot recall, which is a popular and relatively easy climb for views (snag allowing). Also, you will see Comorant fisherman and that will present some interesting photo opportunities. I don't know if a CPL would be of use but wonder if it will help with the haze.
At night, try to see the "light show" if it is available. This is a remarkable production using lights on adjacent terrain and hundreds of locals in costumes. This was originally produced by the same guy who did the opening ceremonies for the Beijing Olympics, to give you an idea of what I am describing.
It has been a few years, but I think we hired a local guide through the hotel. Everything we did while in Yangshou was accessible by walking except the mountain and for that we rented crappy bicycles from the hotel (fine for what we did).
As far as the 14mm is concerned, I have the Samyang variety and not the Canon, but the wide angle might be interesting to use while there.
Sorry to perseverate on the smog but this was a huge issue just about everywhere I went in China.