There are excellent cycling trails along the river valley. Get a copy of the Cycling Trails through Bela Krajina map – routes 1 and 5 are especially good for exploring this area.
On the Hiking Trails through Bela Krajina map, walks 3, 4, 5 and 18 are good. Walk 18 describes the 'Castle Footpath along the Kolpa River', a flat 26km path through the most attractive part of the park, from the sweet hamlet of Žuniči (full of traditional architecture) to Dragoši.
If your main aim is getting on the water, the Kolpa riverbank is home to a couple of the best sleeping choices in Bela Krajina.
There aren't masses of eating choices here; most people spending the night tend to eat where they're sleeping.