I'm in a similar boat now. It seems that I can access my Workshop stuff from anywhere, at least I think I can. However, I can't find my T45 armor. I'm pretty sure I had it, put it away at the Red Rocket station, had something get screwed up, loaded a previous save, and then I wasn't wearing it and it wasn't where I put it. Maybe I put it somewhere and forgot, I'll have to go fishing about.