Need to know what city you want to start the bypass and where are you heading after the bypass. You don't have to be close to the city to start your bypass. There are probably completely different routes you could take from your starting point to your destination.
We have never found a good bypass. We usually go north and cross the Mississippi at Keokuk IA. That involves taking smaller roads. St Louis is one city I never want to drive thru. You could take I-55 north to I-72 and from there west and cross at Hannibal MO.