I have used down/GT bags in northern BC for horsepack, backpack and flyin trips usually lasting two weeks. I DO ALWAYS carry a very light Siltarp and bivy for emergency camps, but, with care a good down bag is fine.
I would recommend a WM Badger for your use, the new "Terralight" is going to be my last down bag purchase soon, but, these are pretty fragile and not as versatile as the Badger, IMO.
Another fine option is the Valandre Shocking Blue, sold mine as I am selling off all my spare gear due to age and health issues, but, it was outstanding on an Elk trip to the West Kootenays in Oct. a couple of years ago and is among THE best bags I have ever used in 50some years.
I would avoid the new ID bags, my 2003 custom XPDII is just superb, but, they are not the same company as they were.
The only other North American-made bag I would now buy is a Feathered Friends, gave my old alpine hunting one to a buddy some years ago, but, they do make fine bags.
I buy my WM gear and lots of other stuff from Bear River Outfitters in Utah, good folks to deal with.