Truman's world was a stage for advertisements, not a prison, a matrix, or a zoo specifically for Truman. It was not about unknowing incarceration, Truman was just a prop. Truman's world needed to be believable for the outside world, the audience, not for Truman himself. People wanted to see the real life, or at least a theme park version. For this to work you need to reproduce the world as it is. Christof needs to take care not to break the suspension of disbelief. He promised to show a "true", everyday life; would you believe that if some of the normal commodities don't exist just for the convenience of the show? A world without buses, world maps, or outside connections is imaginable. But it is an imagination, a fantasy world. It is something different than the promise Christof gave. Truman lives in a clean, idealized town, but it is an imaginable one in the real world.
Also the stage is a workplace for actors. They need to enter, they need to exit daily. As we can see most people are not living full time there (another question could be: Why not?). Nothing is produced there, people don't do real jobs (e.g. the hospital), most buildings are just facades. So while we don't see it a lot of people and material need to be brought into and out of the dome constantly. Some things look like they could be constructed more efficiently, e.g. using a "real" bus service for the people transport instead of installing a unused (unusable) fake overland bus service. But it seems that there was a strict distinction between on-stage props and off-stage material. Everything on-stage was glossy, new, and unused, for advertisement's sake and to create a "perfect" world. Used real things (like real buses) would break this, and probably helped the actors to maintain the distinction as it was obvious when they were in role.
Of course I agree that there are things that could have been done differently in detail. But in general Christof couldn't just get rid of anything that could be potentially harmful to Trueman's naiveté.