The Lofoten Islands won't be nearly so cold; the 20* bag will be ample, if not too warm. I was thinking interior mountains, sorry! On the Lofotens, you are close to the ocean and the Gulf Stream. A beautiful place, if rather wet--take good rain gear! I spent a week there in 2000, staying in the hostel in Stamsund. It was almost like being in a time warp, going out in rowboats to catch cod at midnight and having a fish fry (with everyone contributing to other "dinner" ingredients) at 2 am. If I hadn't had to get back to Germany to fly home, I might still be there!