Culture game is pretty much like any other game until 1AD. Then you focus your empire on GP production and multipliers. You usually bulb all the way to Lib and take Nationalism. All the diplo has to be done to that point and it is pretty possible. You can't always bribe people in wars but you can make them stop trading and other sneaky stuff. Culture is beyond sword in full sense of those words.
Isolation game calls for early as possible Astro. Letting AIs do something somewhere is dangerous and completely luck dependant. If you win culture without means of razing other people's culture cities or capital for spaceship, you should do that before 1800AD. Everything else is pure luck.
Dunno about that..I think the AI will probably find you faster than you can research Astro on deity
