We recently came back from a fabulous trip to Nyungwe.
Very happy with Top Hill Lodge, the forest view and the canopy walk, as well as a fantastic meeting with the troop of colobus.
Instead of driving back through the forest to Kigali, we drove the road going north along Lake Kivu to Kibuye. There are some spectacular views along the way, great peaceful vistas over the lake and the beautiful landscape. Absolutely worth trying if you have a decent vehicle.
The Chinese are working on the first part of the road, and it is good. After that it is good but very rocky, and the last 1/3 or 1/4 is potholed and bumpy, but not problematic.