Mama Murphy is currently in sanctuary and I want her in the red rocket. In build mode, when I look at her it doesn't show anything different, so I can't command or move her. When I talk to her, she says "Mama Murphy's as good as her word kid. No more Chem's, and no more sight either." I tried fiddling with her chair but that did nothing, now she doesn't even want to sit in it. If anyone knows a way to move mama Murphy I'd love to know.
You can't*. Character is essential for Sanctuary location. Especially dialogues are related to Sanctuary.
When you meet her in Sanctuary, she says:
"You're tied to this place, kid. Your energy"
That will be little off if you move Mama Murphy somewhere else like Graygarden where player never was before war.
*Maybe there is workaround with mods/console. But not standard way to do this.