I used a black plastic sled for a few years until I lost it.The sled measured approx 6' long and 3' wide.It worked great even on dry land it made the dragging easier.It had grommets in each corner and along the sides,for tying the deer on.It was lightweight and could be packed in easily.
I would only use it on deer though because the plastic is thin.A person would feel every rock or stick he got dragged over.