There are few better places to go cycling than in and around Yangshuo...
About Cycling in Yangshuo
Despite all the karst mountains, a lot of the actual roads in and around the area are quite flat, making it great for a relaxing couple of hours on the bike.
There's just something incredibly peaceful about watching the small village landscape pass by almost in slow motion as you amble along, marveling at all the karst mountain sights along the way.
Renting a bike in Yangshuo
It can sometimes seem like half of the stores in Yangshuo handle bike rental in some way, but I'd suggest discussing with your hotel directly - they should have a list of bike paths that start and end at the town and be able to get you kitted out on a bike.