Sovereign Tribes?

Native American Tribes in what the Department of Justice calls “Indian Country”  are like sovereign nations, so they can set up systems to allow the sale of marijuana, says the Federal government.  Over 100 Tribes are looking into selling it.

So can a state erect a roadblock and inspect everyone coming out, as a nation can at its international border?  I imagine there is learning on that question, but I have no idea.  Those are questions of federalism or Federal-Tribal law or something that are beyond a tax man.  I know enough to conclude that warrantless federal searches are OK at our borders with the sovereign nations of Canada and Mexico.  But can a state conduct them ever?

And can warrantless searches be effective? Tribal land reportedly is sometimes so remote as to make smuggling across international borders relatively easy.