Enjoy the trip. Did this twice, 2003 and 2016 towing big 5th wheel both times. Take your time and enjoy the journey...the best part. Given your starting point i'm surprised that you don't make the ferry trip on the way home then do the California loop on the way back. We came home crossing the east route at Sweet Grass Montana, it's just a choice. We started in So Cal near Palm Springs. First trip we ferried from Prince Rupert down to Port Hardy and traveled the island south. It was a welcome break after all the driving while headed home. If you have time try and check out the Kenai Peninsula. The drive is beautiful and The trip from Soldotna to Homer is nice. If I ever make the trip again I will home base in Soldotna and salmon fish till my arms will no longer function. Good and safe travels! Watch the roads north of Whitehorse in the YT. They can be un-predictable. Un-matched beauty abounds, more than anywhere I have ever been.
Rick