Once I get my PC built, and am able to play the game with mods, I am looking to get some mods for the Courier Duster. It's great from an RP perspective. Is there any mod which gives you it from the start of the game, rather than having to earn it near the end of the game? It makes sense as something a Courier would wear.

You don't need a mod for one item, you can use the console to add it to your character.