I have smoked venison, elk, and moose roasts several times. One method I have used is similar to the high heat chuckie (pulled chuck roast) method I learned from posts from patiodaddio and adapted to my needs. Here is the cliff notes version.
For roasts from the shoulder or leg
Put rub of choice on meat. Smoke at 300+ until the meat hits a temp of 150-160. Foil with liquid of choice. (dark beer, broth, wine, etc.) Cook until meat hits 200. Rest 30 min to an hour. Pull that beautiful meat, sauce if you'd like, and make yourself an elk sammich.
Another thing I have done with boneless elk/moose/venison is cure (corn) it and then smoke it. (pastrami)
This one I learned from a cool website called the Michigan Sportsman's Forum
For up to 5 lbs. of boneless roast. Needs to be less than 2 inches thick.
5 tbs. Morton tenderquick
3 tbs. brown sugar
1/2 tsp garlic powder
1 tsp ground allspice
1 tsp ground pepper
1 tbs. paprika
Place meat in ziplock. Put mixed cure over meat and work cure into meat. Keep meet in fridge. Work the bag and flip it once a day for 6 or 7 days. On your smoking day, soak the roast for 1 hour in cold water. Pat the roast dry and lightly coat the roast with garlic powder and freshly cracked black pepper. Smoke until roast hits 150.
The last one I learned from years cooking wild game and trying every marinade known to man. Finally I came full circle and realized that sometimes simple is best!
If you have a loin roast get a Weber kettle fired up with the coals on one half of the coal grate. Trim all the silverskin off the meat. Make sure the meat is even in size on both ends. If the roast has a tail end and it gets small you can fold it over itself and tie it so the whole roast is even. Coat with olive oil and rub with coarse black pepper and sea salt. Sear on all sides for 1 1/2 minutes a side over a screaming hot fire. Place the roast on the non-fire side and indirectly cook until the roast hits 130. Rest 5 minutes and serve with the best red wine you can afford. It will be worth it!