That section of U.S. Rte. 18 can be extremely busy, even when RAG isn’t around. There are sections that are poorly maintained. Maybe they’ll fill in the cavernous potholes in the segment ‘twixt Wesley and Britt, but I think it would be a mistake to ride Rte. 18 all day.
I’m not so sure the routing advice for Route 18 was meant to be helpful since the author of the post could not reasonably believe he is the only one with access to Google Map. Rather a way to tell those who voice concerns to stay away.
But you are, it seems an experienced self supported rider, familiar with this highway. Along with the normal traffic and poor maintenance, this will probably be the designated support vehicle route as well as the route for all of those extra sag wagons.
While there are a number of off route options, RAGBRAI discourages this practice. Riding on route is safer in numbers, better maintained, has readily available food and water, and most important the emergency services for rider and bikes. Something this experienced RAGBRAI rider with Google knows as well.
Britt is both a meeting town and is positioned at the 58 mile mark. This will probably be one of the ideal locations for RAGBRAI to place a “SAG Station”, a central location where you can call it a day, and have lunch while waiting your turn for transport. Doing so will at least allow more riders to try and a safe way to exit if 105 isn’t for them.
Rather than Google a straight vehicle route down 18, I calculated a hybrid route on Ride With GPS. So it would retain much of the on-route ride and bypass the 2 U shaped loops, which are there only to increase miles. A savings of 20 miles and little use of Route 18. One of several options I will consider as the time draws nearer.