I visited Way Kambas NP, South Sumatra, in August 2014 and used Hari, an excellent local guide, for much of my time there. The 31 mammal species seen included great views of Pen-tailed Treeshrew, Black-eared Pygmy Squirrel, Indomalayan Pencil-tailed Tree Mouse, six bats; and a brief view of Marbled Cat. Birds included Large Frogmouth, Reddish Scops Owl, Buffy Fish Owl, Brown Hawk Owl, Crested Fireback and White-winged Duck.
Link to trip report (pdf) including photos: 20140816-WayKambas(Sumatra)-PaulCarter-TRv2