Turtling is best with Julii, in my exerience Gauls never attack you, neither does Dacia. Germany has Iuvavum, Lugdunum, and Britons to take care of anyway so it doesn't come near you.
And why does everybody abandon Syracuse? It's so easily defensible! Stone walls and hoplites are all you need agaonst those hastati, and those are both already there!
And either way the Romans go for Lilybaeum first and they leave Messana lightly garrisoned with just faction leader, 1 or 2 hastati. So pretty quickly Sicily becomes a Roman graveyard.