The problem with sleds or carts is that they need to be take in with you and if you move around, what then?
I made a slide from a piece of the heavy blue plastic tarps. I cut it to size and added gromets along each side every foot or so. To use, lay it on the ground, roll the deer onto it, and then use paracord to wrap it around the deer. Attach rope to the head and drag it out.
The whole thing rolls up and fits in a coat packet
