Actually...a name just occurred to me.Call me crazy but...how about Dennis Miller?
I love Dennis Miller, but sometimes his remarks take me too long to think through what he said and he’s already ahead of me until I realize what he just said. He can be very nuanced. Would make a great fill in host though.
Now President Donald Trump would be a perfect interim replacement for Rush, while a permanent replacement is searched for. In fact, have Trump do maybe three days a week and use the other two days to "try out" other hosts for the permanent slot.
Trump would definitely fill the three hours effortlessly and will hold the radio audience together, probably even expand upon it.