I use one of those $5 HDPE plastic roll-up sleds that you often see at the local hardware store. Mine is about 18 x 36 inches with 2 rectangular slots on the front for hand holds. It is very light and weighs perhaps only slightly more than a lexan water bottle (liter size). When rolled up, it has less than a 3 inch diameter.
It is slicker than all get out on the snow! Much more so than shell pants. It is next to impossible to steer it, although leaning and using your feet can help some (still learning). To stop, I find it is best to roll off to the side, although digging in heels or snowshoe claws can slow the thing down in some conditions.
Usually, I only use it on trails that descend directly into the fall line. If the trail traverses the slope, the sled is pretty useless unless there is a lip along the side of the trail. Its not too hard looking at the contour lines on a trail map to figure out which trails have sledding potential.
May have lost at least 1,000 feet of elevation on Moosilaukee's Glencliff trail last weekend on the sled, and that was after putting it away sooner than need be.