What's the road surface like?
Good. You're in the car lanes rather than the shoulder so the surface is clean. There is the odd stray area (the tight hairpin on the Whistler side of Suicide Hill coming back from Pemberton where you can get an area of gravel in the car lane, but that is a very isolated example).
From what I remember there are some areas from the Callaghan back to Whistler where the coning creates lanes that meander back and forth across the white lines on the road, and therefore across the embedded reflectors. Avoiding those little divots in the road requires a bit of concentration (as does working out where the coned lane goes vs where the white lines on the road go).
ETA: just remembered - the flatlands north of Pemberton are a bit bouncy in places. Sub-optimal surfacing, which can shake your head around a bit. I think some of it was resurfaced after 2013 but not sure how much.