@Gsswede: thanks for the suggestions. Maritime Highway sounds very nice but after checking their prices... I think there are a little bit too much for us. But we are looking forward to try the other suggestions.
Once I will know the arrival airport, I'll be able to plan a more clear route for Canada and Alaska and I will for sure take into account your suggestions.
Have a nice trip to South America. I wish you best of luck. In fact, maybe we will see each other as in October I hope to be in Central America too.