re: Does anyone have any tricks or gadgets to get a deer in the bed of the truck?

Yep easiest thing as said is to use a come along, winch, etc. on a tree branch to pick the deer up with. Drive truck or 4 wheeler under it, done.

You could also use a come along from the rear of the truck bed to the antlers and ratchet the head of the deer up over the bed. Then pick the butt up and over or just come a long all the way in.