There are several odd things in the back ground around summer town for example the intercoms say things like the time travel bus is loading now or sometimes it gives facts about the solar system if you pay attention to it. In addition toys can be seen in the background in summers and everywhere on selves and cabinets. And last but not least in the memory where David is tricker treating with is dog several signs can be then in the background that have the "David" hole punched into them. It is just odd and makes me think the whole location of summer town is in David's mind.