Surrounding Paksong and encompassing much of the Bolaven Plateau is the 1100-sq-km Dong Hua Sao NPA, home to large tracts of pristine jungle where you might spot monkeys, large butterflies and rare hornbills. Until recently, wild elephants roamed here but they are gone now according to environmental groups.
Adventure specialist Green Discovery has its zipline and base of operations in Dong Hua Sao NPA, about 15km south of Paksong. This is the best way to experience the park, but you must arrange these tours in advance at the Green Discovery office in Pakse (apparently you can't just rock up and give the zipline a shot).
The treks and tours run by the Tad Fane and E-TU resorts around Tat Fan also get you into the park.