I think that on a randonnée like this one that includes a 90-mile off-road stretch, I personally would not run road tires. This route is designed in such way that the 145 Km off-road section can either make you or break you. The chances of breaking you are much higher. I suggest going with an off-road "event" tire such as the Schwalbe Racing Ralph. It will give you a lot of confidence in the technical and loose off-road sections.