There are many US Canada routes to the Alaskan highway. We chose Alberta having previously been in southern BC several times. From Dawson Creek there is only one major route which is the Alaskan Highway or head up to Dawson City and TOW. At Tok you can travel clockwise or counter clockwise, check the weather and decide.
We enjoyed the Kenai Peninsula and Valdez. We returned via Haines Junction, Haines, ferry to Skagway and Cassiar Highway, Hyder was our last Alaska stop.
There are many other side options not to mention the marine ferry system.