Depends on so many things:
-how fit are you, how strong?
-how big a deer are you dragging?
-how far?
-road? trail? brush? rough/smooth/steep/flat?
-do you have an ATV?
All that said, I have no ATV or truck. I keep a game cart in the car (if fairly firm, flattish ground/trail), plus a Game Glide sliding carpet thing (if snaking through the woods), and an old hoody (if I need to sling a gutted deer across my shoulders). A canoe will likely come into it this year because my stand is across the river. I use the loop on my HSS Ultralight treestand harness that is right at my tailbone to drag deer - really lets you put a lot of power into it. I hook the forelimbs up behind the antlers or ears, as the case may be, tie a noose around that and then clip to my harness and lean into it. Keeps both hands free to steady yourself or move brush. I shoot small deer (max about 150 lbs on hoof) so far, so pretty manageable alone. In case I ever drop a big one, I've got some of those "big game quarter" bags that I could use to carry him out in pieces. Hasn't been a problem yet, but a guy can dream can't he?
Dave