I use a silnylon tarp, a hammock, and closed-cell foam pads. You'd think the hammock would reduce the need for gear, but what it might save (groundsheet) is offset by the needs it introduces (foam pads for keeping your backside warm).

So the weight comes out about the same as for a tent. But I still like the novelty and flexibility hammocks afford. Also, for an older fellow like myself, it gets you up off the ground, providing as it does a chair-height shelf as well as a chair and bed.

I'm talking about a Mosquito Hammock, i.e. one with a built-in mosquito net. Otherwise, you'd have to think about carrying netting in addition to an open hammock.

http://www.mosquitohammock.com/

It's my goal to include a less expensive polyester tarp (at least 8 x 10 ft.), precut paracord tie-downs, aluminum pegs, a bivy sack, and a closed-cell pad in all my vehicle kits. That's my notion of adequate shelter for my environs (Florida).

Bear