I've played JungleIII's practice game to 740AD and I sincerely hope the position in the real game is kinder. In that practice game, Rome is placed right in the middle of the pangea continent and they come at you in hordes from everywhere. I did well early, just about taking out elizabeth with early preats, but when she had one city left, the hordes started to come from all points of the compass. It was Cyrus' immortal/sword combos that took most of England off me again and by 740AD when I 've stopped playing, I'm down to only Rome, and the hordes are breaking against the walls of Rome like water on rock as preats with 50+ experience carve up all comers. It's only a matter of time though - if I played further eventually AI tech at least if nothing else would mean units would come that no preatorian could defeat no matter how promoted.
Archery is needed early in order to survive long enough to use the preats. Maintaining any kind of economy after the hordes start is basically impossible. I did well early, but later on I gave up even using the workers.
The position in relation to other civs on the continent will be critical. As someone has said, choke points and sea will will be useful.
WW is not an issue. It just doesn't happen in all war games apparently.
Even with that though I confess winning this kind of game is looking very hard indeed. It's one thing to survive, but at Monarch with no tech trading ever, (while the AI's trade with each other and are great buddies) no friends ever, and a big enough land mass to make it real difficult to cover in just a few centuries, I'm at loss as to how to win it. If anyone does so, I hope they post a detailed commentary on it in the spoiler thread. I'll play this one to see how I go, but I don't expect to win it - survive a long time maybe, but win? I doubt it!