Well, I think landing was easy because of good planing!
(If one would not praise self, no one will! )
Really, GA give time to transfer units from mainland and firsth original Capac and Franch stack. I only had to cut roads north of cultural space and was able to use roads for a time for hit and run on incoming stack.
So, when Main stack come everything was ready. Yes, AI is bad in usign posible speed of his unit.
Bt I think it would still work, even AI hit as with Copters MI in city with 60% cult defence and on hill should have hold I think.