um... so basically they walked over the top? makes sense.
it would be fairly easy for a cold climate people with canoes to find their way over the top of the world and move down into Canada. No bearing straight bridge needed.
“No bearing straight bridge needed.”
Island-hopping? Why not? After all, “I can see Russia from my porch.” 8^) The converse is also true. People in “Russia” could see that Alaskan island.
“Hey Mook! Lets go check out that island!” And so on. Maybe no land bridge was required?