The whole of Spain can be easily conquered with your starting armies...just make use of your general's bodyguards well. Once you do, just build mines everywhere in Spain and you'll have a huge surplus of income every turn. In fact, the city directly north of Tingis earns me 3k Mnai every turn...

Now the problem comes with expanding my territory beyond iberian lands. I've just snatched Africa from Carthage, and it proved easy enough, with one huge stack of Caetratii and the help of some mercenaries. What is worrying though, is that outside iberia, I simply cannot recruit any of my backbone units anymore. It implies that if I intend to expand my borders to Rome/Gaul/Greece, I'll either have to keep recruiting mercenaries along the way, or keep send stacks of iberian units out from Spain. Unfortunately, the first method is expensive, and mercenaries cannot be replaced easily and quickly. The second will take a very long time, especially when my empire gets too large, and can drain out my Spanish populations rapidly. The natives that I can recruit are not that strong either.

The most threatening point is when I expand to Scythian, Armenian or Parthian lands, if I managed to do it. All my units are at most, moderately armoured; they'll ripped to shreds by horse archers...

Finally, the highest level of settlement that the iberians can achieve is the one with 6000 population. It'll be a pain to manage when I take very advanced settlements like Alexandria, where the population simply explodes every few turns...

Can anyone give advice on how to play Iberia beyond their homeland?