I don't know about the strength of sidewall, but I have been pretty happy with my Duratrac's through all weather conditions. They are on my Pickup truck though and the only "offroading" it sees are farm roads during hunting season (which are narrow, rutted, washboarded, muddy and sloppy) I took a couple wheeling trips with my Wrangler this winter, and I would not recommend KM2's for winter driving. The did fine in cold, powdery snow, but when it gets a little warmer and the snow loses its "bite," they start to suck real quick. They are absolutely terrible (bordering on scary dangerous) in icy conditions.
For what you're doing, you don't see much mud, right? I really think an all-terrain will be better over all for you. You might lose a little traction in the rocks, but you will gain a whole bunch on the road, especially when conditions deteriorate. I ran the General Grabber AT2 on my last pick-up and it was great. It carries the mud and snow designation so it works well in the winter. The only downfall to them is they will pack up with mud and become a slick...plus they pick up and throw gravel all over the place (but that is typical to that style tread, not just the Generals).