While I've never actually smoked one, I have several times roasted one on a spit.
I added a pork fat back inside the cavity as well as stuffed it with baby potatoes, onions, carrots, mushrooms. I used SS welding wire to sew up the cavity. (I think the wire was from a tig welder. Can't remember, got roll from a buddy). I also basted the deer frequently with a mixture of Italian dressing & butter. I injected the same mixture throughout the deer also.
They always come out excellent.