The highway is one of the most isolated in Ontario and among the least-used of the King's Highways. Although the highway is an important access route for several isolated communities, including Little Rapids, Sultan, Kormak and Nemegos, as well as provincial parks such as Aubrey Falls, Five Mile Lake and Wakami Lake, the only community located directly on the highway's route between its termini is Wharncliffe. Services are few and far between on the highway.
Highway 129 is quite substandard in many areas, resembling a secondary highway or low-volume county road with narrow pavement, sharp corners, steep vertical grades and even uncontrolled one-lane bridges. However, due to very low traffic volumes, there is no real demand for upgrades.