Next Steps (Part 2)

Of course, some might say for her to just expand and build a low-level wall around the new area like Fargo did, creating a better-guarded inner wall.

This was indeed the 'best' approach to her situation.

Most territories would opt for an inner wall with the highest level while using a lesser wall for the rest of the territory.

Other than the fact that this would give exclusivity to a 'higher class' of the Lord's choosing, there were plenty of practical reasons for this.

First, high-level walls were too expensive to use in the large area of a territory. 

Second, an inner wall would be far easier to guard during wars because there were fewer areas to guard.

To win a war, the majority of the enemy must get into the highest walled areas. Hence, it would be more difficult for enemies to win because the area they had to get into was smaller and more guarded.