If you go to Yangshuo the best way to see the beautiful mountains and the Li river is to take a bicycle tour on one day (you can probably find a good tour guide via Lisa's Hotel, Quan Hua Tang is a very good guide) You can cycle through the mountain area and visit the moon hill. It is absolute worth to climb the 840 steps to the top. You have got an awesome view from above.

The next day you can take a boat trip on the li river. There is a bustrip to a small vilage, you can visit a school there. From there you can take the boat downstream. We stopped at a very small village where very few tourists go. You can still see how people lived there for centuries. Further downstream you can visit a bigger village. You can go back by boat or arrange a bus to travel back to Yangshuo.