I also played out Sisuitil's 4000 BC save going for Astronomy, just to see how much difference foreign trade routes would help an isolated economy.
To summarize, i went with a heavy CE with scientists. Oracle for COL. 1st 4 GPeople were scientists. 1st for Philo (switched to pacifism right away) in 110 AD, 2nd & 3rd on Astronomy in 815 AD (needed a switch to caste system in 650 AD for timing), and 4th on Education. Won Liberalism race in 1238.
Got lucky with wonders, built both in ankara to keep a pure Scientist pool in capital (ankara founded 1150 BC, Oracle right away). Oracle in 730 BC and then HG in 425 AD.
Got lucky with the progress of the other civs (quite a few wars on both continents). I think 4 civs DIDNT have COL in the 900s AD. I had Astronomy, some COL and maybe machinery here and there on them, and they all went down the feudalism/guilds path on me. I got Monarchy and some junk from my first contact, a Vassalized Huyana, but after that I wouldn't trade nothing. Finally after Democracy I opened up to get Banking for Corporation purposes. My AIs were weak, and their wars were a reason for that. I met Ragnar to find him at war with cyrus ad fred. Cathy attacked Huyana who vassalized to Monty, although a couple centuries after peace. Later, Monty attacked Cyrus, and then everyone attacked Freddie. I went Free Religion and played nice.
Got Lucky with Liberalism, took Nationalism and beelined to Democracy. and then on to a sloppy space.
As far as Astronomy goes, it helped, but maybe not as much as I thought. I wonder if two academies would get a quicker victory. But it did have its benefits. After Optics and Calender I went Currency and halfway through Currency I got the 2nd GS for Astronomy. Finished Currency, then CS, paper and Education w/ 4th GS. But here's the thing. I got my Observatories in before Education, so I could go right on to Univerisities. And Observatories are cheaper too. Another thing for Astronomy is you get first pick of everyone's resources. The extra dye, wine, silk and gems i got on this start was the biggest help. I originally planned to include Monarchy early on but I found that with Confusionist temples, forges and especially the Hamman, I could afford to head straight to Astronomy with size 10 cities in the mid ADs. Trade routes helped some, but i should have kept better notice to get exact numbers. I should play out my 815 save a hundred years to know exactly what they add. But it was the Observatories and resources that helped the most. Later Trade route were huge (as they always are), but hey, every little bit helps.
I also got lucky diplomatically as no one declared on me. The power graph below is pathetic, but I did whatever Monty and Cathy said, except fight in their wars. But i tend to find these things easy to predict and manipulate, especially if everyone hates frederick.
I could've played the end a little tighter and probably should've laid some more cities down and faster, but oh well. Should've had more workers too. Whatever...
Space in 1876
GNP graph
and power
The save just after Astronomy
http://forums.civfanatics.com/uploads/104782/Sisiutil_AD-0815.CivWarlordsSave
1352
http://forums.civfanatics.com/uploads/104782/Sisiutil_AD-1352.CivWarlordsSave
And a turn after victory
http://forums.civfanatics.com/uploads/104782/Sisiutil_AD-1876.CivWarlordsSave