This recipe works with either domestic or wild turkey. The key is low and slow. This is barbecue, not grilling. Set your grill up where the fire is on one side of the grill, and the turkey thighs are on the other. The sauce below is just a suggestion. I like it, but you can use whatever sauce you like.
If you are brining your turkey legs, dissolve the salt in the water and submerge the turkey in this overnight, or at least 4 hours. Rinse and pat dry.
Get your grill ready as described above. Coat the turkey thighs in the vegetable oil. Lay them skin side up on the cooler side of of the grill. Cover and cook until the meat reaches about 160°F, flipping every 30 minutes or so to paint with the maple-bourbon BBQ sauce. For the first 30 minutes, let the turkey cook without the sauce while you make it.
Once the turkey is on the grill, make the sauce by sauteing the grated onion in the butter for a few minutes. You don't want the onion to brown, but you do want it to cook enough to lose that raw onion smell and flavor. This should take 5 minutes or so on medium heat.
Add the remaining ingredients and mix well. Boil this down by 1/3. Adjust for heat and salt. If you want, puree the sauce in the blender. I prefer to puree my sauce because it will be thicker that way. Return it to the stove top over very low heat. Stir from time to time.
When the turkey is done, shift it to the hot side of the grill, skin side down, for a few minutes to caramelize the sauce. Paint with a little more BBQ sauce right when you serve.
Notes
Wood choice is up to you, but oak and fruit woods are perfect here. Only use mesquite if you're using a Mexican or Southwest style sauce.