We will be taking horses/mules into the back country so I dont think weight will be a huge issue.
You could just take another cheap bag and do a two-in-one. It's all about insulation. I wouldn't cheap out on the sleeping pad though. That cold ground will go right through you.
Or maybe take a stove? I mean if weight isn’t a concern I’m not sure why you don’t take a stove.
Obviously it’s no replacement for a bag, but then if your bag isn’t quite up to snuff you just gotta keep the stove stoked.