The Canberra Centenary Trail (CCT) is a nice ride with the exception that so much is through the suburbs. Without directional signage through the suburbs, Komoot will be required to find our way. Canberra.bike suggests that we may as well stay on dirt roads.
CyclingGravel has been out and about and is always good for ideas. This route is from National Arboretum to Campbell via Black Mountain and Ainslie. The route is found in Komoot and on the website. If you do not mind the suburbs this is a good ride.