you can just get bus from yangshuo direct to Xinping then walk the last few kilometres in the opposite to normal direction (as if you were going to Yangdi), then turn back on yourself and return to Xinping when your time runs out,

Seeing as we'd got all the way to Yangdi (about an hour and a half from Yangshuo by bus), we decided to walk north along the river instead. Although we were on a road, there was no traffic and the scenery is, I imagine, very similar to that found on the way to Xingping. There are some small villages to explore and beautiful picnic spots along the river. A pleasant and far cheaper alternative - we did a 3 hour round trip and then returned to Yangdi to catch the bus back to Yangshuo (9.5 yuan each way).

It is far cheaper to get a tour boat in Yangshuo. You basically see the exact same scenery for 100-150 yuan, instead of 350-500 yuan if leaving from Guilin. There are frequent buses between Guilin & Yangshuo. Takes an hour and costs 15 yuan. Accomodation is also cheaper in Yangshuo. Most of the ticketing offices are along Pantao Road & some hostels & hotels in Yangshuo will also make bookings for you. Haggle hard. Some will try & charge you Guilin prices. If they don't drop the price to 150 or less, walk away. There are a dozen other offices next door.

I did the Li River boat tour in late January. It left at about 9 am, went upriver to XingPing & terminated in Yangdi. From Yangdi I caught a public bus back to Yangshuo for 9.5 yuan.