The major highways in St. Louis are interstate 70 (in green), highway 40/interstate 64 (in blue), interstate 270 (in red), interstate 44, and interstate 55. For getting around, you can mostly ignore 44 and 55, though. Also, highway 364, more commonly referred to as Page Avenue (and sometimes highway 3 or highway D) may be useful even though its not on this map.
From Lambert St. Louis Int'l Airport, take I-70 west to I-270. Take I-270 south to highway 40 (I-64). Take 40 west to Maryville Centre Rd.
Take highway 40 east to I270, then I270 north to highway 364 (Page). Take 364 west to Bennington Place, turn right. Go north on Bennington to Marine Avenue, turn left. In the Google directions, ignore any references to Basston Drive--it is a small, one way, local road in poor condition. Also, Google maps gives really bad directions the other way; reverse these instead.