Don't want to second guess you, but your sanctuary really won't be that any longer if you can and will shoot into it if presented the opportunity, correct? If you do shoot something in there, you'll then have to go in and retrieve it, correct?
As far as rifle usage, great! I've been able to use a rifle since starting hunting in WI. What I've found is that I still set up in places where 50 yards is a long shot, so not really necessitating anything more than a shotgun.