Those private spring creeks in the Upper Clark Fork valley are indeed little gems. The amazing thing to me is that they have not been exploited by the ranch owners like the famous ones in Paradise Valley outside of Livingston. I'm very glad that the Upper Clark Fork ranchers have not exploited them.
One of my favorite creeks in the area was the large creek in the valley between Deer Lodge and Rock Creek. It is mostly on private land; but I found the ranch owners very willing to grant permission to fish it if you were courteous and asked. I'm sure you know which creek I'm refering to and its identity shall remain unspoken by me because I don't want to see it over run with fisher folk.
Glad to hear you saw your first Bald Eagle. They are truly majestic birds.