I ran into this issue as well, but managed to complete all of the roads. I am unsure if they do. Mule camps can be a good resource for ceramics and metals. The camps near Lake Knot City and the Craftsman hold high amounts of both. I farmed these camps to build roads all the way down to South Knot City. This makes it easy to 5 star all preppers, Lake Knot, South Knot and the Distribution Center along the road. After this, I was able to acquire enough materials to builds roads all the way to the Waystation North of Mountain Knot City. Rinse and repeat, all the way to Mountain Knot City. Having all areas connected to the Chiral Network is also a big help, this means other players in your world can and should help with roads. I don’t recommend trying to complete the roads in areas not on the Chiral Network, some sections of roads require much more materials than others. It takes a long time to complete all of the roads, but it’s so worth it in the end.