a self-inflating pad will certainly help, but its real benefit is creating a buffer between you body and the ground. if your first concern is padding, look around at some foam pads. they can't compress nearly as much as a thermarest, but they are far more comfortable. ideal would of course be both, but this would bring up the always fun weight issue. a hiker friend of mine doubles up in this way, and he swears by it. so does his girlfriend.
best,
matt b.
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Villin custom touring | Raleigh XXIX | Medici Pro Pista | 1978 Schwinn Stingray