Before I decide what rifle to purchase... check the laws of the state you want to hunt, pertaining to muzzleloaders. Make sure they have no requirements like exposed breech, scopes, etc. Then after you're sure what rifle you can and can not use, pick the rifle that fits you and your budget. Make is a .50 caliber. And a 1-28 twist if an inline.
The Accura, Pro Hunter, Triumph, etc and some of the other top of the line rifles are going to work fine. But if this is a one time hunt, or even a one time here and maybe a one time there... Cabela's has a Tradition's Timber Ridge .50 caliber blue/black that will shoot just fine out to 100 yards for most people. And it costs $89.00. Just find the load it likes, and that is not too hard. I see no reason to spend hundreds of dollars for something that will not be used. Unless your made of money. This rifle is all you would need. Then if you like the sport, pick a better rifle and have the Timber Ridge as a back up or loaner rifle.
Then again, you might like the sport and really get into it. Also I know everyone likes inlines it seems. Personally if I knew that GMB was around and made barrels for my Renegade, I probably would only own a couple White inline rifles and the rest would be traditional rifles. Don't over look the traditional rifle. It will really make hunting interesting and a challenge.