I haven't actually smoked one, but I have done several on the grill. They turned out awesome.
I put it on a rack in a pan to catch the drippings. Salt, pepper and garlic powder over the raw bird. I also like a layer of cayenne, but most of my family doesn't, so I go easy on that. I start with about a half inch of water, wine and apple cider vinegar in the pan. I put a half stick of butter inside the turkey.
I Cook it on low and frequently spoon some of the liquid in the pan over the bird. I add water or broth to the pan if it starts to evaporate, but the lower temp and longer you cook it, the less evaporation. Wrap some aluminum foil around the tips of the wings and legs to keep them from burning.
I usually cook it for about 4 or 5 hours and plan on at least an hour before serving it. When it is done I pour off the drippings for gravy, wrap the bird, pan and rack in aluminum foil and move it out of any breeze. I have never had any complaints. At least not from anyone that was invited back the next year.