The Inner Colonies are linked to Earth almost as closely as the Core Worlds. Most colonists came from the many aspects of life their nation enshrined. And they are located inside The Wall of interstellar debris that separates us from the outside galaxy. Because of that, they are firmly part of Earthspace, and share much more in common with Earth and the early colonies than those outside The Wall. They are worlds full of blending cultural and racial lines.
The reason there are relatively few starships is the cost of hyperdrives. Spaceships are extremely common though. Most star systems are teaming with small ships moving between planets and moons carrying cargo or passengers. People take weekend trips to vacation moons, or perform a daily commute to a job in the asteroid mines. Humanity stretches across every system we have colonized, islands of civilization in the dark of space.
After the Civil War ended, hundreds of thousands of Americans streamed West. Defeated Confederate soldiers, weary Union cavalrymen, farmers, railroad tycoons, and more traveled Westward to make new lives for themselves. They created the Wild Wild West that many still identify with America. The lives of Jessie James, Doc Holiday, Wyatt Earp, and James West are still fodder for stories centuries later. It truly was an amazing time that revitalized a wounded nation.
Did you know dogs were beasts of burden for thousands of years? Horses weren’t used in America until the Europeans introduced them for instance. There and many other places, it was just dogs. I suppose it shouldn’t have surprised everyone when the first uplifted dogs quite literally started pulling their weight and more. By the time I grew up, it was common to see army dogs walking around with heavy weapons strapped to their backs. They can be real intimidating.
The Inner Colonies are those worlds we traveled to soon after Contact. Most were still government colonies, but many of them incorporated at least some Alien technologies. More importantly, they were founded with the knowledge that we were not alone in the universe. They were our first steps into brave new worlds. Gone were the days of leaving Earth behind. We were moving out to meet our Alien friends. We did not understand the limit of our reach in those days.