Due to the way RTW works, you will want to gain control over as many 'shores' as possible. Therefore, your war with the Ptolemaioi is not merely something 'to get your VC's'; it's probably one of the single most lucrative entrerprises your empire will embark on. There are a number of other such lucrative trading hubs: the Aechean, the Black Sea... Also, don't forget that the Persian Gulf and to a lesser extend the Red Sea and the Caspian Sea are not to be dismissed as too much of a hassle to bother either.

Apart from that, mines are always nice; so Baktria & surroundings; as well as the Indos valley and the Caucassus are good pickings too. Plus, if you are smart you can easily keep the Saka at bay with some well-placed armies; and if you control the Indos you can stick a few of those longbow-men for double-duty service too...