I would get the installed, maybe the expansion, but definetly RTRPE. This RTR for RTW 1.5, rather then RTR for RTW with no patches. RTR is fantastic, and I would also recommend some mini-mods as well. The ones I use are Naval Mod, Metro Mod, Roman Leadership Mod, and Four Turns Per Year Mod (rather then 2 turns per year). Naval makes new lines of buildings for ships, and makes them more important (makes the game more historically accurate and better gameplay) Metro mod makes it harder for cities to upgrade, and also adds a new farming method with more lines of buildings also. Roman Leadership mod adds traits which add to your generals, so you can see how long he has been in service, with more years comes higher ranks, and higher ranks mean more bonuses. There is Tribune, Legate, Praetor, and Consul. All these depend on the number of years a character has served leading Roman troops. Once you get certain ranks you get avatars that let you track your legions and consular armies. Fantastic mod. Highly recommended, all.

If you do this, I recommend playing as the Romans first, they are in quite a different position since vanilla RTW. Then Macedon or Carthage are good also.