if you're talking about the Upper Middle Fork Flathead
IF you're talking about the MF Flathead near West Glacier Montana.... I ran it in 1990.
My trip notes were: be ready for bears, moose and mosquitoes, the bushtime counts. Use smart grizzly camping practices, eat on a gravel bar, change clothes, camp elsewhere.
Our on river experience was totally solo, saw no other boaters in three days. Ledge holes and big wide open views with gravel bar rapids and smoking views!
Pretty sweet up there in ole Montana!
American Whitewater has decent beta on it at: