Fort Smith is at the last portage on the water route north and is the only driving entrance to Wood Buffalo National Park.
Fort Simpson is 689 kms west on Highway 5 and 1 (Mackenzie Highway). The town is on an island (ferry runs 6:00 to 24:00) at the juncture of the Liard and Mackenzie Rivers. It is the usual launching point for Nahanni park visits.
Fort Liard is 286 km south on the Liard Highway, which is an indescribably shitty road. It’s a variety from chip-seal to loose gravel to rocks and dirt (when wet it’s a quagmire). Google’s estimate for this part of the journey is 9 hours and 59 minutes.
36 kms south of Fort Liard is the provincial border where one weeps with joy at the crisp line separating NWT chip-seal from beautiful BC asphalt. And 241 kms south of that is Fort Nelson which is in the Peace Valley at bottom of the Alaska Highway.
Next step is north-west up the Alaska Highway towards Watson Lake then Whitehorse.