Opened 5th region...finally!

I'm just over 3 million population away from unlocking my 5th region - also Limestone Cliffs - I'm doing my level best to ignore the population in my main city and focus on upgrading the homes in my regions to hit that magic 10 million. My storage has enough to fill another 4 regions so I'm chomping at the bit to get there! Alas I cannot ignore CoM but assignments to upgrade homes for example is an incentive to help me on my way, and I watch out for any buildings I get as rewards that I can swap out for others that might help add more population. Seasonal Mayor's Pass buildings that are upgradeable are a good way of swapping out landmarks, entertainment etc that have lesser value.