After those 50s strips, Mrs. Van Pelt’s posterior in the first panel is about as much you’d see of an adult. The only other signs of adult I can think of are the speech balloons coming from a house or another room.
Reminds me of an old joke about what a mountain guide told climbers. After telling them what to do to not fall, he said, “But if you do fall, look to your left. You’ll never see another view like that in your life!”
Originally, after Schulz passed away, the Classic Peanuts reruns were supposed to start in 1974, because that was the first year that included all of the major characters (Rerun being the last major addition). But for some reason they decided to go back into the 1960s. I hope they let the strips go into the 1980s. Everyone has their favorite “era” of Peanuts.
Seems kind of unprofessional to talk about them while one is in the room.