My favourite pieces of road in SE BC and SW Alberta. Except as noted, both directions are more or less equal:
SE BC:
Hwy 3A, Creston to Kootenay Bay/Balfour ferry (ferry's free)
Hwy 31A, Kaslo to New Denver
Hwy 6, Slocan to Nakusp to Fauquier/Needles (free) ferry, then to Cherryville
Hwy 23, Nakusp to Galena Bay/Shelter Bay (free) ferry
You probably can't go wrong for scenery on other roads in SE BC but the roads above are for RIDING.
SW Alberta:
Hwy 93, Lake Louise to Jasper (or at least to the Columbia Ice Fields). This stretch of road is the whole reason for a motorcyclist to come to Alberta. To miss this would be like going to the Black Hills of South Dakota and not bothering to see Mt. Rushmore.
Hwy 40 & 541, Hwy 1 to Longview
Hwy 1, Golden BC to Lake Louise
Hwy 1, Calgary to Canmore (heading west provides the climax of scenery, heading east not so much.)
Hwy 1A, Lake Louise to just west of Banff
Hwy 1A, Canmore to Cochrane
Hwy 22, everywhere, but particularly as an alternative to Hwy 2 south of Calgary
Hwy 11, Hwy 93 to Rocky Mountain House
Hwy 762 & 549, Bragg Creek to Millarville
Hwy 533, Nanton to Hwy 22
Hwy 6, Pincher Creek to Chief Mountain border crossing.
