In a situation of chaotic change and lack of knowledge, flexibility and quick responses to new information are key. A group or organization (not just a pre-industrial tribe) lacks precisely that, and has formal and informal group cohesion mechanisms that impede adaptation.

Therefore, I believe a good strategy would be to motivate and assist other Native Americans to leave their tribes, attempt to fare for their own (or for their familiy, warrior band or other small group) in a thousand different ways, and teach others their own solution(s) if it happens to work.