Doing a 4 day-800 mile ride in a few days, so........
Start with a pair of perfectly good Eider ski pants (used to get them free, and they are ugly red).
Cut 'em in half.
Close the ends.
Pack sleeping bag, tent, sleeping pad, down jacket via side zipper.
Zip up the hot dog.
Ride away. You just got bonus points with the wife for saving a bunch of cash. Those bonus points can be cashed in for an extra day riding.