We just got back from 3 days in Yangshuo: travelling with my parents - in their late 70s, but in pretty good shape - and my two children (aged 8 and 11).
It is an amazing place to visit: the scenery is stunning and it's all very accessible. We rented bikes - cycling through the towns is certainly an adventure - imagine every cliche about the roads in China and then multiply by 10. Once out on the open road, or actually the back roads, things got a lot calmer.
Our first day's schedule was built around the standard tourist activities - bamboo rafting, visiting caves, climbing Moon Hill - but the prices, even by Western standards and even after considerable negotiation (I live in Hong Kong so I always haggle) were astronomical. The bamboo rafting was a particular rip off - the price was very high - Y300 per boat (got them down to Y200) for less than an hour; constantly stopping for dams at which photographers take your photo and then try to persuade you to buy.
So the next day we decided to just stick to cycling through the countryside, seeing how the Chinese live, eating at farmer's restaurants. We ended up at a little village called Fuji, I think, and from there we took a boat back to Yangshuo, for one quarter of the price of the previous day's bamboo raft.
We were recommended a wonderful, wonderful guide - Daisy - through our hotel and she really made all the difference. A young student from a local farming family, she had excellent English and really knew her way around.
She took us to great restaurants - the Farms Holday (sic) Inn was fantastic and she recommended another in Yangshuo which became our regular, Mimosa Cafe.
I'd definitely suggest using her and I've got her details for anyone who's interested.
Oh, we did go to the Liu Sanje show - not sure whether it's a must do - again, the price is quite high. It is definitely a visual treat - and also a cultural one - being part of a crowd of thousands all cramming in to the arena - I suppose maybe knowing a bit more about the story in advance would have helped us appreciate it a little more.