Emerald Lake is not in the Wallowas, nor is Crystal Lake. There is no easy access to anything at Riggins from here. Emerald is in a Wilderness area on the idaho side of the Snake River. Joes gap is just a pass one hikes through on the way to Emerald from Black lake, a 3-mile hike. Crystal lake is a difficult hike several miles away. It is indeed a beautiful little lake. As far as fishing, I have always had good luck fishing using Panther Martins as a lure.
Says R Fisk
How is the fishing? Says Dan Rackham
Man, is there plenty of fun stuff to do in the Wallowa Mountains. Lakes? Sure, Crystal Lake is close at hand, and a delightful location to camp here at Emerald Lake is Black Lake Campground.