Here's a nice big overview. During all that conquering, I'd kept researching at an adequate pace, largely thanks to conquer cash. First was Mathematics for chopping ever more immortals, and I also collected Alphabet and the techs for the Great Lighthouse and Oracle.
On the religion front, it broke down very nicely that all the strong civs were Buddhists and the remnants of my conquering had become Hindus. I naturally adopted Buddhism, making for easy friendship with the top three AIs. (I actually conquered but auto-razed the Jewish holy city. That doesn't happen often, and neither does that diplomatic message over there.)
Let me talk for a moment about how not to crash an economy. (Besides being Financial and Organized.) Think about the number-of-cities maintenance cost. It's roughly 0.5 gold for each city you have. Since every city pays the fee, the total cost is roughly 0.5 × N × N, or proportional to N², until you reach the point where it maxes out. Graphically, it looks like this.
(SVG graphics format file. Click for PNG version if your browser sucks.)
There is a danger zone, where each added city costs a LOT, by raising your maintenance cost in every previous existing city. Once you see that number-of-cities cost creeping up to about 5 gold, STOP. The next three or four cities are the biggest economic sinkholes, the ones that add like 20 maintenance and take forever to pay back. Don't go here until you KNOW you can handle it, which usually means some combination of courthouses and Bureaucracy and Calendar resources. Once you get past that steep part of the slope, you can keep expanding and added cities will be close to neutral with Currency and GL trade routes.
Incidentally, why is Bureaucracy so good? (even though I didn't use it early this game) Here's why, also graphically.
(SVG file, click for PNG version)
It doesn't add 50% to the positive part of your output. It adds 50% to all your capital's productivity, such that the addition can be entirely above the "waterline" of expenses. Research multipliers operate only on the "dry land" portion, and cash multipliers operate only "underwater". Bureaucracy thrusts the entire column upwards, like a geologic event on the sea floor creating or raising land on the surface. Currency and the Great Lighthouse do the same thing to a lesser degree, also adding onto the "dry land" albeit linearly rather than multiplicatively.
Take a look at Washington. I really wanted to follow through on this vision for the city: It's got four food resources to serve as a fine National Epic Great Person farm, and could add the National Park for twelve free specialists! Except that a shorter term concern took precedence. This was the only coastal city with the forests to chop out the indispensable Great Lighthouse. Ramesses had a lighthouse in Thebes and a couple hundred hammers in the box so I couldn't take any chance of missing it. Washington would later go on to also chop out the Colossus and Great Library, still being quite an adequate GP farm, but deprived of the explosive National Park. (I never did build the NP.)
Disaster:
Ugh - there's the one thing that went wrong in this whole game. Ramesses built the Oracle. I was four turns of forest chopping away. I hadn't been so audacious as to target Civil Service, but an early jump to Currency would have been very nice. He took Metal Casting, and traded it to me a bit later, so it wasn't too terrible. (I'm not sure I've ever seen an AI take anything other than MC from the Oracle. It's always the most expensive tech available, since they can't plan ahead to sling CS or Philosophy or Feudalism.)
Interesting. Paris was building some wonder, up over 600 hammers in the box. The possible candidates were the Pyramids or Temple of Artemis. I didn't care about the ToA, but I would love for that to be the Pyramids to capture for myself. But how could I possibly tell which it is? I could wait until the city reaches 1050 hammers (the cost of ToA), but that was risky, since waiting might leave me without enough time to build the Pyramids myself.
Got the answer: Gift my stone to France! Sure enough, Paris's hammer production doubled from about 12 to 24. And when I did get Alphabet, France turned out to lack Polytheism anyway, so definitely the Pyramids.
So I attacked France. I got paranoid in case it had a spearman, so waited a little while to replenish the stack to 10 immortals. But there were only two archers and the city fell easily.
Back home, I had run two scientists in Babylon using the city's ample supply of food and a whipped library. So it spawned my first Great Person. I wanted the academy in the capital of course, but had to pop the Golden Age right now for many reasons. It saved four turns of anarchy to Org Rel and Representation. I needed Org Rel right now to kick in Ramesses' fave-civic bonus towards getting him to trade his Metal Casting monopoly. I needed Representation right now for the happy boost since Calendar was still quite a while away. And I needed the Golden Age economy now to get to Currency thanks to failing the Oracle.
Currency took 8 turns to research during the Golden Age, then Code of Laws, going for that before Calendar as better trade bait for Metal Casting. CoL is fine to give away, pushing the AI towards Philosophy for you, while for Calendar I'd rather have more time for the Mausoleum.
Nice. I do believe having bought Ramesses to war with Brennus was key to this. Without that distraction, he probably would have built his Industrious Forge sooner and started on the Colossus too soon so he wouldn't trade MC. (Friendly AIs will trade a monopoly tech, but will still refuse if they're building a wonder with it. That's the message "We have our reasons.") I chopped out the forge and Colossus quickly.
My next tech path was NOT Civil Service. Bureaucracy would be 3 turns of anarchy. As good as Persepolis was, that anarchy was a net loss against just waiting for the next Golden Age. No, I went for the artsy-faffy stuff next, Aesthetics - Literature - Drama. The Great Library was worthwhile (I've skipped it sometimes without marble), plus we wanted the National Epic and Globe Theater.
Then Machinery, which landed a nice trade. I picked up another tech and more easy mutual-struggle kudos, while getting Ramesses to clean up the leftovers of France for me. (De Gaulle now had a few spearmen so Immortal conquering was over.)
My second Great Person then spawned from Washington, as a low-odds Engineer! Nice, that takes care of Mining Inc with no headache. Engineers aren't easy to get, as we know. My plan in other attempts at this had been to stack up in one city the Pyramids, Hanging Gardens, maybe Hagia Sophia, and an engineer specialist, hoping that the city would eventually sneak in the GP rotation ahead of the National Epic city. That wouldn't work right here thanks to the Pyramids being over in Paris, so it was nice to have this out of the way.
And China popped a Great Scientist, so I flipped him Drama cheap. Bam, he bulbed Philosophy. And because he was Friendly he easily traded it to me (had to do that right away before he started on Angkor Wat.) Just as good as bulbing it myself and another great research timesaver.
Speaking of popping... 
. Although it's at that National Epic city, which would rather be working a specialist than a mine, heh heh.
Paid a Feudalism demand... now that's what I call a strong friendship! And see he's researching Theology, more juice to trade to me, and like with Philosophy I had to do it immediately before he started building either wonder. Ramesses went on to build the Apostolic Palace in Buddhism for me; I always enjoy getting that free ride.
Anyway, my research after Drama beelined up to Banking. Not Civil Service or Education. Everybody loves Oxford University, but it wasn't the right move here. That thing is expensive, needing 3000 hammers worth of universities that aren't going into settlers. No, the renaissance economic flashpoint to chase is the Representation - Mercantilism synergy, which has the awesome property of being *free*.
