We normally do 5 or so miles over the posted speed limit, never slower than the middle lane of traffic on a three lane road. Please remember that where we are coming from we're dealing with Philly, Baltimore, and DC traffic--and that can add a couple hours anyhow onto the trip if you don't catch it just right. We refuse to drive 85 mph like some people do, it's just not worth the risk to get to WDW an hour faster...
Anne