The only thing that can slow you down is if the RJ is full and you have a bag that you "checked" right before you boarded the plane (with that lovely PINK tag). Usually they are pretty prompt returning the bag once you deplane but recently I was on an RJ from SDF-CVG and my bag was the last one off and it took about 10 minutes to get me the bag and I was off and running for my connection in B terminal.

The bus trip from C to B is usually pretty quick and most time there is a bus either waiting or just a moment away.