I note WashU is located on the St Louis city border in a former “streetcar suburb”, a type of development form sometimes also called “semi-urban”. I tend to like that term because it helps distinguish such areas both from denser central city locations but also later-built auto-centric suburban areas.
Anyway, there is a walkable commercial district, along a restored street car line actually, the Loop Trolley (seasonal only):
There is also Forest Park immediately across the border, which has a LOT of amenities.
And there are also Blue Line Metro stations basically on either end of campus, which you can use for quickly getting into the Downtown St Louis area, or transfer to the Red Line for access to the airport:
Just some details in case people are interested in the quirks of WashU’s setting.