Sleeping bag advice

If you are in the U.S. consider REI's sleep sack for $50.00 - it weighs 1.5 pounds and packs down pretty small.

You should be able to get a 5degC semi-rectangular bag which weighs around 800gm or so (around 1kg with its stuff pack and a liner). Mummy bags are going to weigh less, but I find it difficult sleeping in them. I found 5degC sufficient. I think a 15degC bag would have been less comfortable when I walked in Apr. Pilgrims with bags rated at that temperature were not always comfortable, and some admitted to being positively uncomfortable, and not getting a good sleep at all.

Some forum members will advise that you can do most Camino routes relying completely on blankets provided by the albergues. My view is that this limits your choices, and there a number of places where I stayed where having the sleeping bag made that possible when I walked. It meant that I didn't have to worry about whether or not blankets were available before deciding where to stay.

The fact that a gift is inappropriate for what you are planning to do should not create a moral obligation on you. If it's too late to discuss whether or not they could negotiate an exchange for a more suitable bag, let them know that while you appreciate their gift, but you had this dilemma and had to choose a different bag.

Regards,

http://www.midwayusa.com/product/2723258223/snugpak-sleeping-bag-liner-thermalon
Try one of these, stretchy and you don't feel constricted, or one of these
http://www.deuter.com/en_US/sleepingbag-details.php?artnr=37071&category=132&title=Dreamlite 500