In my current Brutii campaign (VHard/VHard) I am about 15 years into the game, and I have 20 provinces & 150k in the bank. It is probably the easiest fraction I have ever played. Here is what I did:

[Stage 1]: City 2 -> 4

Occupy the rebel town (Senate mission) in turn 1, then occupy the rebel town just north of it. Ship all available armies, diplomat and spy east to the Balkan pennisula. Turn one of the starting cities into a troop producing base.

Note: Senate asked me to blockade the Carthagians on Sicily; I ignored.

[Stage 2]: City 4 -> 7

Arrange an alliance with the Macedonian, attack and enslave all Greek (not Macedon) settlements there incl. Athen. Turn Sparta into a Principe mass-production base for its already-built 2nd level barrack, and sign a ceasefire with the Greek. Move your capital to Athen for its already-built Academy. (Good for young family members)

Note: Senate asked me to blockade the Greeks on Sicily; I ignored.

[Stage 3]: City 7 -> 11

Break the alliance and attack Macedon with everything. Exterminate every town from this point (unless its population is < 1000) and destroy Macedon as soon as possible. Quickly generate a lot of troops from the Macedonian cities. There will be a plague in the old Macedonian capital at about 250BC (which I haven't encountered), so don't leave family member(s) there.

[Stage 4]: City 11 -> 14

Field a 2nd army to occupy the Crete Island. Hire as many Crete archer mercenaries you can because they are the best archers you will have for dozens of years. Then, land 2 armies simultaniously to the Greek cities on the east side & Rhode to avoid all the struggle with the might Greek navy. Declare war to the Greeks again and occupy both cities in one turn. Cease fire (and ally) with the Greeks again.

[Stage 5]: City 14 -> 20 (I am at this stage now)

In the meantime, field a 3rd army to the northeast for Thracians & then Scy*ians (sorry can't spell). Field a 4th army, which also heads north but turns west to handle Dacian. Field the 5th army to expand towards Sicily. In my game the impotent Roman Scipii hasn't expanded any further in Sicily.

Continue the eastern expansion with army no.1 & 2. Declare war to the Selucid Emprie and Pontus and keep going east while picking up rebel colonies. Ally with the Egyptians and Numadians to stay out of naval threat.

Hope this helps.