When heading out on a long back pack trip where keeping weight to a minimum is essential, we have found great luck with waterproof bivy sacks. They weigh in at a couple of pounds and fit into a very small stuff sack. You won’t have the joy of sharing a tent together, but they are easy to unroll and climb into. The main thing is getting use to the feeling of being inside what amounts to a body bag. I find that on clear nights, I get over the creepy, claustrophobic feelings by sleeping on top of it, or by sleeping with the head portion unzipped and pulled down around my chest. Happy sleeping!
