I agree about towing the sled; I just mentioned it because that is how I travel part of the time. But, if you are going off trail, track skis won't cut it. They are just too narrow, don't have an edge and are too hard to turn. Off trail, I would use either snowshoes or wide skis, even wider than mine, if the snow is really fluffy. I learned that lesson last winter in Yosemite.
We could argue about this all winter, but my suggestion to the OP is just try whatever you can find and see what works where you are.
If anyone wants to learn more about backcountry skiing, here is a good place to start- http://tinyurl.com/r6tts