I did a few events with them albeit more than 10 years ago now.
It’s not closed roads, you ride with the traffic. I did London to Paris and although it’s open roads the route was chosen to avoid busy roads. It was well waymarked and you got a route guide as well. These days I guess you might be able to get a GPX as well. The food stops were well organised with a good choice of food with great hygiene standards, and although we didn’t need it mechanical support was very good as well.
The events I did were VERY well organised and supported. I did the Machu Picchu trek with them and paid the cost of the trip myself (roughly half) and got donations, did boot fairs etc to raise the rest. When my friend was taken ill at Dead Woman’s Pass, the support was superb. The weather was such that a helicopter evac looked unlikely so they had porters running in from Cuzco overnight with a stretcher and an additional Dr, so the Dr who was on the trek could stay with the rest of the group. In the end she was helicoptered out and the additional Dr went with her. Absolutely faultless planning and execution.
I’d go with them again in a heartbeat.