Mike7
WKR
I use a bivy/sleeping bag cover for the exact reasons Aron mentions. But I still use Tyvek under my sleeping pad and to put my gear on under the tarp tent to keep it off of the wet ground. The Tyvek is very light and also compact, but has its faults. It is noisy (which I don't mind) and it is very slick, which I do mind sometimes and can be a problem if there is any slope to the ground.
So this year I may try the polycryo ground sheets like those sold by Gossamer Gear (I've heard they're not so slippery as the Tyvek). The ground sheets protect your inflatable pad, are dirt cheap, and can double as an impromptu rain shelter/pack cover during a quick storm, or a place to lay meat on while butchering.
So this year I may try the polycryo ground sheets like those sold by Gossamer Gear (I've heard they're not so slippery as the Tyvek). The ground sheets protect your inflatable pad, are dirt cheap, and can double as an impromptu rain shelter/pack cover during a quick storm, or a place to lay meat on while butchering.