Use a basic rotisserie and your grill for one of the easiest and best tasting ways to roast venison.
Pre-heat the grill, all burners on high.
Tie the roast up. Cut a piece of twine about 6 ft long. If your roast is a flatter cut, roll it into a tube. If it's thicker, once you start tying it, it should "round" up.
For an easy tie up, find the middle of the twine and place under one end of the roast. Wrap it around, pull it tight, and make a knot. Flip the roast, wrap the two ends of the twine around, and tie another knot, an inch or so away from where you first placed the twine when you started. Flip it over and repeat till you make little loops an inch or so apart across the whole roast. If you pull the twine nice and tight with each loop, you should end up with a nice round tube shaped roast.
Rub the tied roast with olive oil, and rub on your spices.
Take a square of aluminum foil a little bigger than the roast. Fold up an inch or so on each side, and pinch the corners to make a drip tray/heat deflector.
Put the roast on the skewer of the rotisserie, tighten the forks, and put it on the grill.
Place the drip try you made under the roast, and turn the rotisserie on.
Close the grill. Turn off the burners directly under the roast. Adjust the burners on either side of the roast till the temperature settles between 250 and 275. I find with a 4 burner grill, with the two center burners off, and the two side burners at about 3/4 full (medium high), it settles in to the perfect temp.
Wait an hour and check the temperature of the meat. You are shooting for 135 to 140.
If it's not done yet, check it every 10 minutes till it hits your preferred doneness level.
Take it off and let it rest for 15 minutes (uncovered).
Eat it right away, or if your are slicing it for sandwiches, wrap it in foil, and refrigerate a few hours or overnight, then slice.
Serve with any jus collected during the rest/slicing phase!