Unless you are very interested in Chief Mkwawa or Tanzanian hi story, it's difficult to justify this dusty museum's price. It's also possible to arrange with the caretaker to visit other nearby historical sites, including a cemetery with the graves of some of Mkwawa’s 62 wives, and the site of part of Kalenga’s old defensive wall (the ruins themselves are now nonexistent).
Kalenga is about 15km from Iringa on the road to Ruaha National Park. Dalla-dallas go regularly to Kalenga (Tsh500) from Iringa’s post office, also stopping at Mlandege bus stand near the round about at the start of the Ruaha road. Ask to be dropped at the signposted turn-off, from where it’s an 800m walk through the village to the museum.