I have decided to set the transport level ofmost regions to tracks. The exception would be those regions in Italy traversed by Roman Ways at the time, like the Via Appia, Via Aemilia, Via Salaria, etc, and the Via Heraclea along the coast of Spain and Southern France. For those regions I would set the level of Roads, as Major Roads seem way too fast according to what I experienced in NCP.
BTW It would be interesting to have the graphics for Major Roads to this regions with Roads level, would that be possible?