I suggest choosing Lvwan Lake in Heyuan as the first choice. It is beautiful and the water quality is good. There is rafting by the lake of Guishan, which is very thrilling. Heyuan is located in the northeast of Guangdong, with good air and good greening. Accommodation is not expensive and folk customs are simple.
Nankun Mountain is too close to Guangzhou, and there are too many people on weekends. Facilities and management are very problematic. It is said to be a scenic spot in 4A, but I think it can only be rated as 1A. Nankun Mountain is short of water and has a wide range of mountains. There are several local towns, which are rather chaotic.