Here are some maps for reference
For some context, in my world, from 2030-2040, an event known as the Great Collapse saw the human race pushed towards the brink of extinction due to Unidentified Colossal Organisms/UCOs rising up from their ancient hibernation in order to rampage and cause chaos and destruction across the planet, leading to the deaths of billions along with the collapse and even extinction of entire countries, peoples, and cultures.
Out of the over 350 individual UCOs that rose up, the largest, strongest, most destructive, and most powerful of them all, Godzilla (who stands at over 500 meters tall), was directly responsible for directly killing over 850 million humans on all seven continents while also being directly responsible for the collapse of tens of countries along with battling and killing dozens of other UCOs that challenged Godzilla. It doesn’t help that Godzilla is the only known Apex-class UCO to have been discovered, making him the top of the planet’s food chain.
Anyway, Godzilla’s territorial realm extends across the entire Pacific Ocean/Pacific Rim and includes large swaths of land in Asia, Oceania, North America, and South America. In the United States of North America, after Godzilla ravaged what was once the Western United States of America and British Columbia (which now form the Godzilla Continental Exclusion Zone) and forced the mass evacuation of over 50 million people, the USNA military fortified the Rocky Mountains and established the Western Defense Line, the most heavily fortified and militarized border on the planet stretching from Fairbanks, Alaska down to Phoenix, Arizona, in order to defend against Godzilla and any other UCOs in the Exclusion Zone.
My idea so far involves the Western Defense Line having over 60,000 troops in total. The WDL has 12 massive fortresses call Battle Stations lining across the entire Defense Line in strategic locations, with there also being eight Command Battle Stations that oversee a particular sector of the WDL (the Battle Stations and Command Battle Stations look like the Shatterdomes from Pacific Rim). Each Battle Station has 3,000 troops stationed there and is fully capable of being self-sufficient, with each Battle Station having their own ground and logistics units and a dedicated air wing. Each Battle Station is also equipped with two Massive Ordnance Projectile Cannons, which are the largest artillery pieces ever created capable of annihilating entire city blocks and shooting at a target 60 miles away.
But what else should I keep in mind when creating heavily fortified and militarized borders? What should I add and/or avoid doing?