Direct route from Sonora to Vegas to Salt Lake City Boise Seattle. Moscow and Pullman right there, isolated and Nez Perce Reservation right nearby.

from old NYTimes article:

Law enforcement officials say Mr. Oakes and the drug lords he is accused of stealing from are part of a violent but largely overlooked wave of trafficking and crime that has swept through the nation's Indian reservations in recent years, as large-scale criminal organizations have found havens and allies in the wide-open and isolated regions of Indian country.