Next week my Family's spending a day in your city, any attraction/food/traffic tips?

Title says most of it- family of 5 (parents + kids ages 20/18/15), driving down from Minneapolis, spending 3 days in MO. One day at Six Flags, one in St. Louis, one relaxing. We're obviously going to visit the arch (seen it twice, now I actually get to go inside!), I heard mentions of the zoo. Anything else can't-miss? Any parking tips?

Food wise- we want St. Louis style BBQ while we're actually in St. Louis, we were thinking about Pappy's, but I saw in the favorite foods thread a mention of Bogart's; so now I'm caught between the two. My parents had also tossed on Ted Drewes, and I'm going to try to convince them to go to Carl's Drive-In.

Traffic wise- anything to avoid? Any major corridors knocked out? Thanks in advance!