My mileage on TrainerRoad is pathetic, because I keep the bike in a low gear. Zwift wants you to mess up your trainer in a high gear.
One of my problems with a 200k is I am pretty sure people are driving too fast out in the boonies. I don't have any routes that really protect from that. Cyclist injuries are way up due to reckless driving. The one I really want to do is mostly on gravel, but it would be extremely tough without stops. It's bad enough even with stops.