[Caramelgal]

The early coastal migration is one such source; people came from the vicinity of Alaska and traveled down the west coasts of both North and South America before the poor folks trudging through Canada got very far.

Since sea levels were lower during this period due to heavy glaciation it would make sense that the overland route across Canada would have been a very arduous and slow going journey to say the least. And there is some evidence based on the study of coast marine and fauna life dating to the period of the earliest American and South American human settlements found thus far, that suggests that due to warmer and favorable ocean currents, the coastal route would have been much more hospitable and very feasible.

"People coming down the coast could have been doing the coastal equivalent of island-hopping," he says. "We are not envisioning a coastline bordered by towering walls of well-established ice. Conditions were highly variable along the coast and I think that there were some significant open areas. Early travellers were familiar with such environments in areas to the north, so this was nothing new."

Such “island hopping” would not have required sophisticated boat building or navigational skills. And given the choice between trudging across thousands of miles of frozen glaciers on foot and tracking Mammoth or Bison over such harsh terrain or going by boat; hugging the warmer coastline and hunting in grasslands and fishing and gathering abundant marine life, I think I’d rather take the boat.

[Coyoteman]

I agree with both of your points.

In addition to islands, you would have had river mouths with sandbars as potential stopping-off places. The farther south, the more favorable these would have been even during the ice age.