Gwabi Lodge is happy to organise backpackers. It is on the border of Lower Zambezi, not far from Chirundu. They offer canoeing or boat cruises along the Kafue and Zambezi Rivers. They also take guests into Lower Zambezi on safari.
To get there from Lusaka take a bus to Chirundu. A taxi ride from Chirundu will take you to the lodge.
Coming from Livingstone, it will be necessary to take a bus to the turnpike (the T-junction north of Mazabuka). From there catch another bus to Chirundu.