If you can find any route that lets you dodge the interstate, do so. In most of the US interstates have a minimum speed of 45 mph, and you can be ticketed for going below the minimum speed. Interstate shoulders also tend to be pretty dangerous, since they don't get cleaned the way a surface street does.

How indirect are the indirect routes? I've lived in places where the only way to cross major rivers was an interstate... that could put a real cramp in your commute.