I haven't started my build yet, but as an experienced bicycle guy, I would tell you to look further than a road bike, such as yours. At moped speeds, that ride is going to be very hard and bumpy. You'll want something that runs at least a 2" tire to smooth things out, and a road bike won't accommodate those rims/tires. I would use a mountain bike, preferably with some suspension, and a quality tire like Continental Town & Country's or a similar tread pattern.