Way to go Trapper, nice deer.
I keep a plastic sled around (aka icefishing sled) just in case I get lucky. I'd load the deer in the back of my truck by pulling the head and neck up to the back of the truck or in your case up to the tailgate. Tie it off so the head is up over the edge, then pick up the back legs and roll the deer by any means possible into the vehicle. I know it's no easy feat, especially with back problems. I sure know about them.
Did you gut the deer on your tailgate? All the coyotes within miles will be trailing you home. If the deer is hanging up outside, keep your eye on it...they like to eat the tail end...