In Idaho, there are many Choices. My favorites that I try to visit often.
1.
Selway River Trail. 50 miles along the Selway River, some of the most remote wilderness in the world. From Race Creek in Idaho to the Montana border, this trail has not much elevation loss or gain, but is beautiful the whole way. Because of the low elevation, it is one of the first trails to be clear of snow each spring.
2.
Seven Devils Loop. Lots of elevation gain and loss. Beauty with alot of climbing possibilities as well. There is still a body of a hiker to be found up there. They found his dog still alive in October.
3.
Toxaway Petitt Loop Actually one of my favorite hikes. Gorgeous views in the Sawtooths of Idaho with lots of side trail options. You could easily hike in here and spend a month hiking, and not want to go back home.
4.
Grand Sawtooth Loop No description needed, just click the pics.
5.
Big Baldy-Indian Creek Loop 52 miles of serious elevation gain, and not many people. When I did this hike, I only saw three people in five days. Very remote area, largest protected wilderness area in the lower 48 states!