Yangshuo to Guilin, which way is best?

Hi - i plan to travel in October and my route is Hong Kong to Yangshuo to GL to Kunming however I wanted to experience the Li River between YS and GL. Everything I have read up says the cruises only go down river? Is this the case? If so, are there any alternative options to see parts of the scenery travelling up? I have considered changing my route and reversing between the two however the transport links are better from GL too so I would like to depart for Kunming from here too. Any help would be much appreciated. Thanks in advance