Has anyone tried sleeping inside their sleeping bag, inside a SOL Escape Bivvy, or vice versa? Thinking about ways to not have to buy a Winter bag and a Summer bag for an AT January start. It would be great to have a pretty warm 3 season bag for the whole thru-hike and not to have to fork out money for two bags, and it would also be great to not freeze in the winter or burn up in the summer. The main goal is to be able to get through both extremes without switching bags. Suggestions, comments, advice, free money? I'll take it all.