I think a lot of things came together perfectly in that game. I don't think I could repeat it so I haven't even tried.
@Aigburth, that's definitely a very good game. If I may give some constructive criticism though:
First of all, you're absolutely right that the shape of that continent is far from perfect. It's pretty far from your core to the farthest AI (Aztecs? I guess they're a nice replacement for Inca I use), and that certainly cost you some time, not to say a lot.
But also, something I learnt from Drazek way back, "it's the last city that counts". In this case, you don't stand to gain very much in attacking the Maya, their core won't be productive more than a settler or three until the end. So the constraint you have to work with is, how fast can you conquer the Aztecs (and fill in the gaps of course)? Sending your army to attack the Celts first and then the Aztecs, and use the troops built last to attack the Maya, could likely have saved you a few turns.
All in all, it's the military prowess where you fall behind. In my 1425 BC game, it took me <10 turns from starting my GA to having taken out the AI to the point of crippling them (though they were closer at hand which made it a lot easier). In the 1275 BC game it took ~15. I never saw the end of my GA.
Find a better map, with you in or near the center, and I'm sure you can improve that date.
Gee, now I feel like playing again, even if I don't think I'll beat that date in a million years. But I'll try to beat the 1275 BC date again.