I am assuming that you still need insulation...if not I got a simple air matress at rei that was 7 in thick, 29 wide and only 4lbs to carry. I have also owned ba insul air core 2.5 in thick and they are pretty nice at 1.5lbs. A couple years ago I upgraded to expeds synthetic insul air mattress at 3.5 and it is heaven at only 2.5 lbs. Exped makes the best mattress I have ever used. At thickness for the weight, I couldn't buy any better at the time and their valves are the most bomb proof too.