I will share a little of my experience a few years ago I did 3x 100+ Miles Fondo Days _ I was doing unstructured training at the time but did back to back days of 50+ miles to try to build up the strength / recovery necessary for doing the back to back days. So if I was giving you some advice I would suggest you do some back to back rides in the plan, get your nutrition on track and make sure you fuel your rides and recovery. Good Luck