I tried 20K in test game, in a much worse random start (on a lake instead of a river, no hills but still Luxs in a city radius, jummed into continent's corner), and saw that it's doable.
I got Oracle, Pyramids and Glib in AA, missed Monarchy slingshot but got good trades from Phyl, build Cath/Library/Collosseum in the BCs. Things got tougher in MA as AIs got their land improved, it was impossible to get any of the required-tech wonders. But I got optionals: Bach and Shake's (and KT - ina cascade), and can probably get Smith as AI isn't bothering researching for it.
I never got to use GS! I had no Iron, and when I got it it was too late - got GA from Pyramids&Oracle (should remember this combination...). I was weak throughout, but still had something like 5000c+59cpt in 9th century.
So it's doable, and I'm almost convinced to do it. Especially if there's no other religious Civs.