From the Alaska Hwy 97-Cassiar Hwy 37 Junction point A :
To the Cariboo Hwy 97-Yellowhead Hwy 16 Junction at Prince George point B :
The distance factor between point A and point B here the last I knew was a 28 mile distance shorter if the Cassiar Hwy (Hwy 37) was taken, however there is no way you will make time on it compared to the Alaska Hwy route (Hwy 97) to Prince George if that is your destination route.
The Cassiar Hwy is narrow with no shoulder throughout as the northern half is bumpy in parts while the southbound half is smooth as glass, however it is scenic and has hills and a few grades in between with more curves and yes it has its same elements of the far north roads with floods, fires, and bridge work (other far north roads are no different) - as logging trucks are king on the Cassiar route....once you reach Hwy 16 it is good road with wide shoulder as you are back on the modern roads as commuters drive rather fast on it.
The northern rockies south of Liard Hot Springs (mile 477) on the Alaska Highway has some intermittent 6% to 9% grades but nothing compared to the Sierras and is short lived, lots of curves between Liard Hot Springs thru the south end of Steamboat Mountain (around mile 320 or so) as you can make up faster time south of that on the Alaska Hwy and beyond.
I have yet to be stranded ever in the four Septembers I driven thru Summit Lake highest point at 4200 ft. due to potential snowfall that hadn't arrived but it could happen....mid October for that area is the average timeframe to worry about snowfall there unless it is an earlier coldfront that will linger.
Seeing parts of a trucker blog posting, the basic mentality and goal for a trucker is hauling a load from point A to point B the fastest way possible, period.
Unless there is an ocean, a ferry dock, a barge deck, a flagger, or a destination point B at the end of the road, no trucker is going to slow down any while driving on land no matter what the road conditions are other than eating or sleeping in between destinations.
If you want to drive to the states in the fastest way possible, as mentioned stay on the Alaska Highway and go thru Grande Prairie via Alberta Province.