Idaho wilderness use depends on accessibility and reputation.
The Pioneer and the Boulder mountains near Ketchum are minimally used except for day hiker favorites Hyndman Basin, Pioneer Cabin and the Summit Creek Trail off Trail Creek Summit. We saw only two backpackers in further reaches of the White Clouds beyond Castle Peak pass but encountered dozens of campers at Chamberlain Lakes, 8.5-10 miles on good trail from Fourth of July Road trailhead.
The Sawtooths, a world-renowned wilderness with glaciated lake basins, jagged toothlike peaks and a first-class trail system, are heavily used. Easily reached trailheads from Pettit Lake, Decker Flats and Redfish Lake off Idaho 75 and near Stanley attract the most hikers. Some make loops between alpine lakes, and others base camp at a lake basin. Outfitters offer day trips or pack-ins by horse and mule to some lakes. We saw dozens of people; I counted 38 day-hikers and two horseback riders on the trail to Sawtooth Lake.
Campsites were few; we sometimes spent an hour looking for a good flat spot — even at well-known lakes. The Sawtooth National Recreation Area grudgingly allows campfires, but old fire circles are scattered. This shortage channels campers into a few well-used areas with multiple routes to campsites. A better solution would be shoveling out and marking a few camp areas near each lake.
In the Salmon River Mountains, we saw few people except near good trails or roads. We met no backpackers on the Middle Fork Trail, but it may be too hot in early August at this low (3,000- to 3,600-foot) elevation. We saw hundreds floating or camping along the Middle Fork — commercial raft trips but also independent kayakers and floaters. River floaters were friendly, curious and generous, offering food, rides and beer.
The Bighorn Crags on the northeast end of the Frank Church are well-used. A Forest Service wilderness guard we met had seen 120 hikers in the past week. We saw a couple of dozen; most were base camped at a lake basin and taking long day hikes. Like the Sawtooths, the Crags offer good stock trails for many loop options. Outfitters provide pack-in services for hikers and fall hunters.