If your travelling that far on a sled, you may want to consider a folding plastic/tarp style(ie: The Clam or Clam JR) I know Walmart sell an similar 2 & 4 man one for much less. Then built or buy a sled to haul it and your gear, with a direct hitch system. I think you'll find dragging a wood shed to be a huge problem, that distance. Unless you plan to leave it there for most the winter or for extended periods of time. BTW The Fishin Hole has plans and actual packages to build one like Hog! mentioned, I am not sure what the cost is though. We built one a number of years ago, although transported in a 1/2 ton and it cost us about 500 to build using top notch black tarp. However the tarp/wood does take some serious wear and needs to be replaced about every 5-7 years.

We use a small propane sunflower and tank, it will roast us out of our 4 man wood/tarp or my Clam. The bonus with propane heat is it doesn't make you sleepy.