They may have walked along the beach when they could, and built crude vessels when they could travel only by water. And it's the only way, so far, to explain how they got to South America 14,000 years ago. tried to follow the route of those early settlers today, he would find it a very difficult task.
Their are many things that would have made it difficult to travel across America. Lack of real transportation made it difficult and the long vigorous journey too.
