Here is what I did:
This assumes that we reaserch Pottery at 100%.
Turn 0: Settle on Spot, Move worker to cow, Start Settler, City working Cow
Turn 1: Mine the Cow
Turn 5: Finish Mining, Start Roading
Turn 7: Finish Roading, Move to Wheat, City grows to size 2, New citizen works wheat, grows in 4 finished settler in 5, Rasie Lux to 10%
Turn 8: Worker Irragates
Turn 10: Culture expands
Turn 11: Settler Finishes, Start Granary(20), Irragation Finishes, Start road
Turn 13: Road Finishes, moves into city
Turn 14: Move to Ivory
Turn 15: Road Ivory
Turn 17: Irragate Ivory
Turn 18: City grows, New citizen to Wheat, Grows in 4, Granary in 13
Turn 20: Finish Irragation
I'll continue playing later.
So far it seems as if we should Mine the Cow and then road the Ivory because Irragating the Wheat did not help get the first settler out any faster. We would then have the Ivory connected at Turn 8, which means we only have to raise Lux for 1 turn. We would then go Irragate the Wheat.