Right after Sue Ann chews Mary out for 'depriving' Lou of the trip to Chicago, the establishing shot of Chicago includes, (on the extreme right) where Dr. Bob Hartley's office of The Bob Newhart Show (1972) is. That series was also an MTM Enterprises Productions show.
Sue Ann mentions her first show: a cooking show in Chicago, entitled; 'Let's Talk About Meat.'
The waiter who brings the drinks when Mary and Sue Ann are out with the morticians, is Robert Karvelas, best known as agent Larabee, on Get Smart (1965). Mr Karvelas last appeared in this series in the 3rd season episode, Mary Richards and the Incredible Plant Lady (1973), as a mechanic