Roast turkey is liable to turn into turkey jerky when dehydrated. Also, unless you are cooking low-fat, the meal is liable to turn rancid after a couple of warm days.

If you want to dehydrate turkey, cook it moist (preferably pressure-cooking) and low fat, and then grind it before dehydrating as CamperMom suggests. Take stuffing mix plus chicken bouillon cubes or powder; add hot water and oil when mixing in camp. You can dehydrate mashed sweet potatoes (leave out butter) and buy freeze-dried green beans. Of course dried cranberries are easily found. I don't know if there is such a thing as turkey gravy mix (I am not a gravy fan), but you can use a chicken gravy mix.