In/near Sawtooth National Recreation Area, check out the Redfish Lake Campgrounds. I think there are 5 or 6 and some of them are non-reservable. We stayed in Outlet Campground which has some great sites. Also try Stanley Lake. I think there were a couple of sites large enough. If you want to boondock, there are plenty of places along that road, on your right as you travel north on 75 up to Stanley.
Check out the Stanley Baking Company if you pass through the area. They have a really great breakfast.
http://www.idahocampgroundreview.com/redfishlakearea.html
