The Alaska Highway starts in Dawson Creek, British Columbia. It continues through the Yukon Territory and officially terminates in Delta Junction, Alaska (although many people think it ends in Fairbanks AK).
The Highway has undergone many improvements in past decades. Generally, it is good driving, with much of the highway being two-lane with some shoulder. Most of it is paved, which is not a good thing in some areas as the surface becomes rough from the continual thawing and freezing.
The best advice is to take your time and enjoy the scenery.