Agree with all comments above. You are going to have to slow considerably on hills of any size due to wall to wall huffers & puffers; plus, takes time to get thru intersections, etc. In my opinion, you’ll lose a couple mph average due to these reasons. And the IHP has been known to totally close the route for quite a while due to accidents requiring ambulance or air evac. Average speed should not even be considered on Ragbrai. In fact, other than using a computer to know where the upcoming towns are, it would probably be more enjoyable not to even have one!