Settled 1NW per advice. Early tech path was Ag -> AH -> BW - Wheel, then on to Sailing, Masonry, and Mysticism in some order that escapes me. First four cities nabbed resources (Horses, then Copper, then Stone on that island to the south) before I started expanding toward Pacal. In the meantime I was rolling up wonders. Given the slew of islands to the south, Great Lighthouse seemed obvious, so I got it, the Oracle (Metal Casting), the Pyramids, and the Colossus while expanding to the east and into the islands.
I got an early GM thanks to the Lighthouse, so I sent him to Bibracte for a trade mission. Early gold on that scale meant I could crank the slider up to 100% for a good long while. Teching was ridiculous thanks to cottage spam and the Colossus, and Lighthouse-fueled trade routes with lots of island cities (plus Noble, of course) meant that my economy was easily staying afloat.
Mid-game tech path was basically an Optics beeline with a quick dip to Aesthetics. Got early Caravels in the water and found the
huuuuuuuuuge other continent, then won circumnavigation easy. The hilarious part about this was that neither me nor Genghis nor Boudica nor Pacal had teched Alpha yet! I ended up getting it and Archery in a backfill trade with Darius, but I was miles ahead by that point and didn't really need it.
Around this time I built the Shwedagon Paya for early Free Religion. Since I'd met the other continent early, I settled on them as long-term allies with the possibility of a backstab later on. Mansa was good for some tech trades, but I had a pretty good lead on him and mainly used him to backfill. Ultimately, I think this was the move that won me the game.
Genghis DOW'd around this point and sent some galleys full of troups over to my Moai city (that boomerang-shaped island just north of the southern continent). At this point--and with my tech rate still rolling along at a ridiculous pace--I made a mistake and decided to tech Astronomy for Galleons to protect my southern flank. I figured I'd make up the lost Colossus income through overseas trade routes, but it didn't quite work out, and I didn't have enough surplus resources to trade for gold anyway. Early Astro wasn't so hot on that front, but being able to ferry support to the front was nice.
Next tech path was to Guilds for Knights, but I rolled along quickly enough that by the end of the troop spam I was able to upgrade them all to Cuirassiers, which I then used to smash Pacal. Boudica DoW'd and actually managed to capture the Moai city, but it was easy to get back. She brought in Genghis (they were buddy-buddy aaaaaaaaaaaaall game), who proceeded to use Sun Tzu's military strategy of Not Doing a Damned Thing. Cuirs killed Pacal, and by the time the war was over I'd built up a fleet of Galleons, some Frigates, and had teched Rifling.
So Boudica and Genghis didn't take long to roll over. I had sued Genghis for peace earlier since he had a nice purse of gold, but none of my peace-loving buddies on the other continent cared that I declared again later. Boudica went down quickly but built something like a zillion Triremes, which my Frigates tore apart. I took all of her cities since I was hoping Domination was possible just by grabbing this whole continent as well as mine.
Then I got Washington's map in a trade, and. Uh.
So Boudica got killed easily, and it wasn't hard to start rolling up Genghis. The best they could field against Cavalry were Longbowmen/Pikes, and near the end of the Celtic War I had Infantry for garrisons (I'd gotten Assembly Line through Liberalism, hilariously enough... did I mention Noble AI techs ridiculously slowly?

). I decided near the end that I'd just khapture all of Khan's khities... errr, cities... and go Diplo.
So I captured Khan's last city, and... immediately a vote comes up.
AP Diplomatic Victory.
Um.
The AP was Jewish (which was nobody's state religion), and Mansa held it, so he was the only candidate.
And then Mansa won an AP Diplomatic Victory.
Despite not being Jewish.
...yeah, okay, no, that was the dumbest thing I'd ever seen. I didn't even know he could do that.
Reloaded the last auto-save.
THIS TIME I left Khan with one city, took his capitulation, and spread Taoism there (I'd founded Taoism and Confucianism by accident... did I mention the Noble AI techs slowly?) to make Mansa's job harder. Then I sold Mansa Electricity, Radio, and Mass Media in subsequent turns. I also sold Darius Liberalism to let him switch into Free Religion for the "wisely chosen Civic" Diplo bonus before revolting to US, cranking down the slider, and building the UN in my Ironworks city (in that hilly country north of the capital).
The good news is that my rival was Washington, who had expanded like mad post-Astronomy and grabbed whatever lousy islands I hadn't settled in that archipelago. By that point Darius was at Friendly thanks to resource trades and running FR, Mansa was at Friendly because I'd been trading with him all game, and Genghis was Annoyed but didn't have much say in the matter.
Before long...
Diplomatic Victory in 1820. Later than I'd normally like, but I'd have gotten it out
much quicker if I'd done a more strict Mass Media beeline, maybe getting Radio from Lib.
So what worked on this map?
* Great Lighthouse! The trade routes are always nice, but I can't overstate how much getting an early Great Merchant helped. Just a quick trade mission to the southern continent let me power my way through the mid-game, which in turn afforded me the luxury of teching Liberalism at my leisure.
* Early Optics! In my game, Pacal didn't explore at all (AIs won't trade much when they've found only you and nobody else), and the only other two AIs within reach were two lunatics with utterly lousy land. The other continent had very diplo-friendly rivals on it, so I was able to build up goodwill diplomacy early on for the later win.
* Shwedagon Paya! Normally I like using OR to spread the faith and build infrastructure, but being able to run FR early--especially thanks to the GM-powered economic boom--helped both diplomatically and with rolling up techs.
* Late Golden Ages powered by the Mausoleum! Kept the war machine humming and the economy moving nicely once the GM money ran out.
What did I do wrong?
* Teching Astronomy too early with the Colossus in hand! This was especially dumb as a Financial leader like Victoria, I think.
* Leaving weak garrisons on my southern flank next to Boudica and Genghis Khan of all people! I hate losing cities, especially on Noble. That city should've been bristling with Longbows, but I kept garrisons weak mid-game, and Boudica took advantage. This is an easy thing to neglect when building a trade-based economy powered by intercontinental trade routes since there's already a lot of ferrying things around.
* Having a muddled game plan near the end! At various points I had Diplomacy, Space Race, and Domination in mind as victory conditions. Had I just stuck to Diplomacy, I'd have won it much earlier.
* Not pressing the Maya earlier! I probably could've spammed Horse Archers and taken care of him early on, or even built the HA's and used merchant money to upgrade them to Knights later. Pacal didn't build much for me other than the Hindu shrine, so it was probably worth it to take care of him early.
* Underestimating AP cheese! Seriously, what
was that.
So I was kind of screwing around, but this made for an interesting map. I'd never really messed with a trade route economy, and it's powerful stuff. Different game than what I'm used to on the whole.