Without an Idaho license, I would try fishing above Asotin on the Washington side. Drive through Clarkston and follow the signs past the town of Asotin. Lots of bank access above town , on the Snake. Fly fisherman work the bar in front of the restaurant at Three mile, and all the way up to and including the Grande Ronde River mouth area. The best months for me have been October and November. Good luck. Go Cougs!