Mpulungu zambia to Lusaka public transport options?

Hello, My wife and I are catching the MV Liemba from Kigoma July 28th. When we arrive in Mpulunga we need to take public transport to Lusaka. Does anyone have advise on this route? What company, what time? How long? Etc?

Thanks very much,

FYI: The Central Line Train from Dar to Kigoma is out of service until at least mid-August. Only Air Tanzania is flying to Kigoma right now. Book early.