[Ironhawk]

Fenris99: If you want to pursue a turtle strategy against the AI, then the most important thing to do is control the bottleneck provinces. Instead of having a wide border with the AI, try to find the key provs which control access to large parts of your empire's interior. If you control the bottle neck provinces and put a ton of PD into them, the AI will brainlessly just keep ramming itself into them with no hope of victory. In this way you can gain almost perfect protection from the AI with the least investment.

Also, you probably dont want to build a fort in those provinces, just so you dont have to constantly remember to tell your commanders to Patrol (if they are set to Defend they will sit in the fort while the enemy takes the province around you).