[Question_Assumptions]

But some archaeologists argue that due to the nomadic characteristics of America's first settlers, the seemingly difficult feat of traversing both North and South America in 1,000 years is not

They would not only have had to be very nomadic but able to adapt to the multitude of changing climates (each containing a different mix of new plant and animal life) as they travelled from North to South America. That is a pretty tall order.

[SauronOfMordor]

They would not only have had to be very nomadic but able to adapt to the multitude of changing climates (each containing a different mix of new plant and animal life) as they travelled from North to South America. That is a pretty tall order.

As Physicist pointed out, that's only 10 miles/year. We don't know what kind of poulation pressure would have impelled them to keep moving as new people crossed over behind them. If we assume a coastal fishing people, they could move their villages large distances without trouble and not caring that much about minor changes in climate