After she & Walter get to the hotel room, they close the blinds on the front door. As the show goes on, the blinds go from shut, to open and shut again several times, with neither she or Walter touching them.
When Maude rants "who am I", Walter answers that she is his wife. She then says she was also "Barney's wife, and Andy's wife and what's-his-name's wife." Multiple times before and throughout the series it's stated that Maude's three husbands were Albert, Barney and Chester. There was no Andy.
When Walter and Maude get back to the John Smith Motel after attending the convention, the top of the motel room set is visible for a few seconds after Bill Macy turns the lights on. If you look at the top of the screen, you'll see a small space. The camera stays pointed in that direction until it pans to the right when Bill walks off to one of the other rooms.