I spent a summer as in intern with Burlington Northern RR in Livingston in 1978. The Yellowstone and the Shield Rivers were excellent and didn't get much traffic at the time. Dan Bailey's Fly Shop is a good reference: http://www.dan-bailey.com/.
Those were the days- work, fish, release all but one 14 incher, cook and eat it, then play five card low stud with the locals till bedtime. Simple is good.