Steve,
I was not familiar with SMD, but when I looked it up it looks like great stuff. I have used tarps and tarp tents and find them fully functional for most weather conditions. It is partly psychological, but I still prefer a double wall tent for snow camping. I'm still climbing, but I try to stay away from places that require me to carry crampons, rope and gear. Good luck with your "new" adventures. I can testify to the fact that there can be plenty of enjoyment and rewarding trips without bagging summits.