A buddy of mine got me started using a Jet Sled... used for ice fishing... you just slide your deer into the Jet Sled, slides great on leaves and snow, pick up the front end of the sled and rest it on the tailgate, then pick up the back end and slide it into the truck bed.

One man can load a BIG deer and slide it into the truck with ease.

Plus you don't need to hose out the truck bed as all the blood stays in the sled.

Mine is camo, so I use it for hauling duck and goose decoys, and storing gear.