I absolutely LOVE deer roast in the crock pot. It comes out so moist and tender. I usually add a little water to the bottom, enough to get some moisture in there. I also add carrots, onion, celery and salt & pepper to taste.
If you have left overs, you can pull the meat, add your fav BBQ sauce and make BBQ sandwiches. Yum Yum!!
Like Va said, get rid of the silver skin and the fat. That's where you'll get a lot of gaminess. If it's a yearling, I don't bother taking that stuff off, as it's not old enough to have developed that gamey taste. Sometimes, it just makes the meat better.