CVG is actually a decent airport for transfers. Not anything like ATL. Much less confusing and easier to get from terminal to terminal. My MCO->CVG plane landed in terminal B. THe shuttle to C was one gate over. The bus was waiting for us as we got to the bottom of the escalator. I could see one or two more lines up waiting as well. The same for getting from C to B on the HVN->CVG leg.

Assuming all is on time, 40 minutes should be plenty. I had less than 30 and didn't even have to 'huff it' to get from B to C or vice versa.