You can make up any excuse you'd like, character-wise, to skip Concord. My main point is just that I believe what I posted in my original post was the main story path Bethesda designed, and that Concord and Red Rocket got tacked on at some later point.
My character's reason (before I knew any of this) for skipping going home was simple:
She was WITH her family in the Vault. She saw her husband die. Saw her baby stolen. And she saw the nuke hit outside the Vault. She assumed the house was gone - and even if it wasn't, the pain of returning without her family was too much of an idea to entertain.
There is actually an extra bit of dialogue with a certain fellow pre-war survivor if you haven't returned home to Codsworth. They mention your "damned, robot" still "pruning the bushes", and you can react with real shock. "Wait, Codsworth ... is ALIVE?!" It's a good little scene, and finally gives a motive to go get the robot on a visit home.
EDIT: But it is nice to see that Bethesda did include lots of motives and dialogue for things to still make sense if you skip around and don't do what is "normal". The game is a lot more malleable than people give it credit for.