I suggest you take a walk along the Bin Jiang Road the first day. En route, you could enjoy the beautiful night scenery in Guilin, especially the Double Pagodas. The second day, you may cruise down the Li River to Yangshuo. Then have a short trip to the countryside to enjoy yourself in Yangshou. Transfer back to Guilin. The third, You can go to visit the Reed Flute Cave, the Seven Star Park and the Elephant Trunk Hill.
Wish you a wonderful journey!