I would suppose forty days from Lilybaeum to Ariminum was about right considering they would have had to cross the Apennines at some point. They probably were taking their time, too, comparatively.

Am I right to say that the Polybian quote comes from Tiberius Sempronius Longus' march to join Gnaeus Cornelius Scipio near Clastidium prior to the battle of the Trebia?