Robert Allen you are a lucky man. Do you guide somewhere else in the off season? I was just name dropping on the Madison. A few years back I bought 20 acres over there with the thought that when my sons (now 10 and 13) get into high school and college that if I had a cabin over there it would be a pretty darn cool place to row a boat for someone and pick up a few bucks as a summer job. That is great country over there, my older son shot a 6pt bull and a mtn goat over there this year. Truely an extrodenary year, he caught his first steelie last year.
e7 lots of good advise on this thread, like rt said the best bet would be july, mid july. I'd also be flexable on which river to hit as they all have hot and cold spells and like all rivers you can't always predict them (or the weather very long in advance. Good Luck and oh ya don't forget Freds.